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#include <iostream>
#include <vector>

using std::cout;
using std::cin;
using std::endl;
using std::vector;
int board[8][8] = {
  {-5,-3,-2,-6,-10,-2,-3,-5},
  {-1,-1,-1,-1,-1,-1,-1,-1},
  {0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0},
  {1,1,1,1,1,1,1,1},
  {5,3,2,6,10,2,3,5},
};
bool check_w(){
    int row;
    int col;
    bool found = false;
    for (int i = 0; i < 8; i++){
        for (int j = 0;j < 8;j++){
            if(board[i][j] == 10){
                row = i;
                col = j;
                found = true;
            }
        }
    }
    if (found == false){
        cout << "There is no white king on the board " << endl;
        return false;
    }
    if (row != 0 && col != 0 && board[row-1][col-1] == -1) return true;
    if (row != 0 && col != 7 && board[row-1][col+1] == -1) return true;
    int a;
    int b;
    a = row;
    if (row != 7){
        for (;;){
            a+=1;
            if(board[a][col] == -5 || board[a][col] == -6) return true;
            if (a == 7 || board[a][col] != 0) break;
        }
    }
    a = row;
    if (row != 0){
        for (;;){
            a-=1;
            if(board[a][col] == -5 || board[a][col] == -6) return true;
            if (a == 0 || board[a][col] != 0) break;
        }
    }
    b = col;
    if (col != 0){
        for (;;){
            b-=1;
            if (board[row][b] == -6 or board[row][b] == -5) return true;
            if(b == 0 || board[row][b] != 0) break;
        }
    }
    b = col;
    if (col != 7){
        for (;;){
            b+=1;
            if (board[row][b] == -6 or board[row][b] == -5) return true;
            if(b == 7 || board[row][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 0 && b != 0){
        for (;;){
            a-=1;
            b-=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 0  || a == 0 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 0 && b != 7){
        for (;;){
            a-=1;
            b+=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 7  || a == 0 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 7 && b != 0){
        for (;;){
            a+=1;
            b-=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 0  || a == 7 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 7 && b != 7){
        for (;;){
            a+=1;
            b+=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 7  || a == 7 || board[a][b] != 0) break;
        }
    }
    if (row > 0 && col < 6 && board[row-1][col+2] == -3)return true;
    if (row > 1 && col < 7 && board[row-2][col+1] == -3)return true;
    if (row < 7 && col < 6 && board[row+1][col+2] == -3)return true;
    if (row < 6 && col < 7 && board[row+2][col+1] == -3)return true;
    if (row < 6 && col > 0 && board[row+2][col-1] == -3)return true;
    if (row < 7 && col > 1 && board[row+1][col-2] == -3)return true;
    if (row > 1 && col > 0 && board[row-2][col-1] == -3)return true;
    if (row > 1 && col > 0 && board[row-2][col-1] == -3)return true;
    if (row != 7 && board[row+1][col] == 10) return true;
    if (row != 0 && board[row-1][col] == 10) return true;
    if (col != 7 && board[row][col+1] == 10) return true;
    if (col != 0 && board[row][col-1] == 10) return true;
    if (row != 0 && col != 0 && board[row-1][col-1] == 10) return true;
    if (row != 0 && col != 7 && board[row-1][col+1] == 10) return true;
    if (row != 7 && col != 0 && board[row+1][col-1] == 10) return true;
    if (row != 7 && col != 0 && board[row+1][col+1] == 10) return true;
    return false;
}

vector<int> push(int row,int col,int desrow,int descol){
    vector<int> move;
    move.push_back(row);
    move.push_back(col);
    move.push_back(desrow);
    move.push_back(descol);
    return move;
}

void undomove(int original,vector<int> Move){
    board[Move[0]][Move[1]] = board[Move[2]][Move[3]];
    board[Move[2]][Move[3]] = original;
}

int perform(vector<int> Move){
    int original;
    original = board[Move[2]][Move[3]];
    board[Move[2]][Move[3]] = board[Move[0]][Move[1]];
    board[Move[0]][Move[1]] = 0;
    return original;
}

vector<vector<int>> generate_moves_w(){
    vector<vector<int>> pseudomoves,legal_moves;
    vector<int> move;
    int original,a,b;
    for(int row = 0; row < 8; row++){
        for(int col = 0;col < 8;col++){
            if (!board[row][col]) continue;
            if (board[row][col] == 1 && row != 0){
                if (row == 6 && board[row-1][col] == 0 && board[row-2][col] == 0)
                    pseudomoves.push_back(push(row,col,row-2,col));
                if (board[row-1][col] == 0)
                    pseudomoves.push_back(push(row,col,row-1,col));
                if (col != 0 && board[row-1][col-1] < 0)
                    pseudomoves.push_back(push(row,col,row-1,col-1));
                if (col != 7 && board[row-1][col+1] < 0)
                    pseudomoves.push_back(push(row,col,row-1,col+1));
            }
            else if (board[row][col] == 5){
                a = row;
                b = col;
                if (a != 0){
                    for (;;){
                        a-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a!=7){
                    for(;;){
                        a+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (b!= 0){
                    for(;;){
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a  =row;
                b = col;
                if (b != 7){
                    for(;;){
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }

            }
            else if (board[row][col] == 3){
                if (row > 0 && col < 6 && board[row-1][col+2] <= 0)pseudomoves.push_back(push(row,col,row-1,col+2));
                if (row > 1 && col < 7 && board[row-2][col+1] <= 0)pseudomoves.push_back(push(row,col,row-2,col+1));
                if (row < 7 && col < 6 && board[row+1][col+2] <= 0)pseudomoves.push_back(push(row,col,row+1,col+2));
                if (row < 6 && col < 7 && board[row+2][col+1] <= 0)pseudomoves.push_back(push(row,col,row+2,col+1));
                if (row < 6 && col > 0 && board[row+2][col-1] <= 0)pseudomoves.push_back(push(row,col,row+2,col-1));
                if (row < 7 && col > 1 && board[row+1][col-2] <= 0)pseudomoves.push_back(push(row,col,row+1,col-2));
                if (row > 1 && col > 0 && board[row-2][col-1] <= 0)pseudomoves.push_back(push(row,col,row-2,col-1));
                if (row > 0 && col > 1 && board[row-1][col-2] <= 0)pseudomoves.push_back(push(row,col,row-1,col-2));
            }
            else if (board[row][col] == 2){
                a = row;
                b = col;
                if (a !=  0 && b != 0){
                    for (;;){
                        a-=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a !=  0 && b != 7){
                    for (;;){
                        a-=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));

                    }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 7){
                    for (;;){
                        a+=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 0){
                    for (;;){
                        a+=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
        }
            else if (board[row][col] == 6){
                a = row;
                b = col;
                if (a !=  0 && b != 0){
                    for (;;){
                        a-=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a !=  0 && b != 7){
                    for (;;){
                        a-=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));

                    }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 7){
                    for (;;){
                        a+=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 0){
                    for (;;){
                        a+=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a != 0){
                    for (;;){
                        a-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a!=7){
                    for(;;){
                        a+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (b!= 0){
                    for(;;){
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a  =row;
                b = col;
                if (b != 7){
                    for(;;){
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }

            }
            else if (board[row][col] == 10){
                if (row != 7 && board[row+1][col] <= 0)pseudomoves.push_back(push(row,col,row+1,col));
                if (row != 0 && board[row-1][col] <= 0)pseudomoves.push_back(push(row,col,row-1,col));
                if (col != 7 && board[row][col+1] <= 0)pseudomoves.push_back(push(row,col,row,col+1));
                if (col != 0 && board[row][col-1] <= 0)pseudomoves.push_back(push(row,col,row,col-1));
                if(row != 0 && col!= 0 && board[row-1][col-1] <= 0)pseudomoves.push_back(push(row,col,row-1,col-1));
                if(row != 0 && col!= 7 && board[row-1][col+1] <= 0)pseudomoves.push_back(push(row,col,row-1,col+1));
                if(row != 7 && col!= 0 && board[row+1][col-1] <= 0)pseudomoves.push_back(push(row,col,row+1,col-1));
                if(row != 7 && col!= 7 && board[row+1][col+1] <= 0)pseudomoves.push_back(push(row,col,row+1,col+1));
            }
        }//col loop
    }//row loop
    for (long unsigned int i = 0; i < pseudomoves.size(); i++){
        original = perform(pseudomoves[i]);
        if (check_w() == false) legal_moves.push_back(pseudomoves[i]);
        undomove(original,pseudomoves[i]);
    }
    return legal_moves;
}

int main(){
vector<vector<int>> legal_moves = generate_moves_w();
for (unsigned long int i = 0;i < legal_moves.size();i++) cout << legalmoves[i][0] << " " <<  legalmoves[i][1] << " " <<  legalmoves[i][2] << " " <<  legalmoves[i][3] << endl;
return 0;
}

#include <iostream>
#include <vector>

using std::cout;
using std::cin;
using std::endl;
using std::vector;
int board[8][8] = {
  {-5,-3,-2,-6,-10,-2,-3,-5},
  {-1,-1,-1,-1,-1,-1,-1,-1},
  {0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0},
  {1,1,1,1,1,1,1,1},
  {5,3,2,6,10,2,3,5},
};
bool check_w(){
    int row;
    int col;
    bool found = false;
    for (int i = 0; i < 8; i++){
        for (int j = 0;j < 8;j++){
            if(board[i][j] == 10){
                row = i;
                col = j;
                found = true;
            }
        }
    }
    if (found == false){
        cout << "There is no white king on the board " << endl;
        return false;
    }
    if (row != 0 && col != 0 && board[row-1][col-1] == -1) return true;
    if (row != 0 && col != 7 && board[row-1][col+1] == -1) return true;
    int a;
    int b;
    a = row;
    if (row != 7){
        for (;;){
            a+=1;
            if(board[a][col] == -5 || board[a][col] == -6) return true;
            if (a == 7 || board[a][col] != 0) break;
        }
    }
    a = row;
    if (row != 0){
        for (;;){
            a-=1;
            if(board[a][col] == -5 || board[a][col] == -6) return true;
            if (a == 0 || board[a][col] != 0) break;
        }
    }
    b = col;
    if (col != 0){
        for (;;){
            b-=1;
            if (board[row][b] == -6 or board[row][b] == -5) return true;
            if(b == 0 || board[row][b] != 0) break;
        }
    }
    b = col;
    if (col != 7){
        for (;;){
            b+=1;
            if (board[row][b] == -6 or board[row][b] == -5) return true;
            if(b == 7 || board[row][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 0 && b != 0){
        for (;;){
            a-=1;
            b-=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 0  || a == 0 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 0 && b != 7){
        for (;;){
            a-=1;
            b+=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 7  || a == 0 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 7 && b != 0){
        for (;;){
            a+=1;
            b-=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 0  || a == 7 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 7 && b != 7){
        for (;;){
            a+=1;
            b+=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 7  || a == 7 || board[a][b] != 0) break;
        }
    }
    if (row > 0 && col < 6 && board[row-1][col+2] == -3)return true;
    if (row > 1 && col < 7 && board[row-2][col+1] == -3)return true;
    if (row < 7 && col < 6 && board[row+1][col+2] == -3)return true;
    if (row < 6 && col < 7 && board[row+2][col+1] == -3)return true;
    if (row < 6 && col > 0 && board[row+2][col-1] == -3)return true;
    if (row < 7 && col > 1 && board[row+1][col-2] == -3)return true;
    if (row > 1 && col > 0 && board[row-2][col-1] == -3)return true;
    if (row > 1 && col > 0 && board[row-2][col-1] == -3)return true;
    if (row != 7 && board[row+1][col] == 10) return true;
    if (row != 0 && board[row-1][col] == 10) return true;
    if (col != 7 && board[row][col+1] == 10) return true;
    if (col != 0 && board[row][col-1] == 10) return true;
    if (row != 0 && col != 0 && board[row-1][col-1] == 10) return true;
    if (row != 0 && col != 7 && board[row-1][col+1] == 10) return true;
    if (row != 7 && col != 0 && board[row+1][col-1] == 10) return true;
    if (row != 7 && col != 0 && board[row+1][col+1] == 10) return true;
    return false;
}

vector<int> push(int row,int col,int desrow,int descol){
    vector<int> move;
    move.push_back(row);
    move.push_back(col);
    move.push_back(desrow);
    move.push_back(descol);
    return move;
}

void undomove(int original,vector<int> Move){
    board[Move[0]][Move[1]] = board[Move[2]][Move[3]];
    board[Move[2]][Move[3]] = original;
}

int perform(vector<int> Move){
    int original;
    original = board[Move[2]][Move[3]];
    board[Move[2]][Move[3]] = board[Move[0]][Move[1]];
    board[Move[0]][Move[1]] = 0;
    return original;
}

vector<vector<int>> generate_moves_w(){
    vector<vector<int>> pseudomoves,legal_moves;
    vector<int> move;
    int original,a,b;
    for(int row = 0; row < 8; row++){
        for(int col = 0;col < 8;col++){
            if (!board[row][col]) continue;
            if (board[row][col] == 1 && row != 0){
                if (row == 6 && board[row-1][col] == 0 && board[row-2][col] == 0)
                    pseudomoves.push_back(push(row,col,row-2,col));
                if (board[row-1][col] == 0)
                    pseudomoves.push_back(push(row,col,row-1,col));
                if (col != 0 && board[row-1][col-1] < 0)
                    pseudomoves.push_back(push(row,col,row-1,col-1));
                if (col != 7 && board[row-1][col+1] < 0)
                    pseudomoves.push_back(push(row,col,row-1,col+1));
            }
            else if (board[row][col] == 5){
                a = row;
                b = col;
                if (a != 0){
                    for (;;){
                        a-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a!=7){
                    for(;;){
                        a+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (b!= 0){
                    for(;;){
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a  =row;
                b = col;
                if (b != 7){
                    for(;;){
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }

            }
            else if (board[row][col] == 3){
                if (row > 0 && col < 6 && board[row-1][col+2] <= 0)pseudomoves.push_back(push(row,col,row-1,col+2));
                if (row > 1 && col < 7 && board[row-2][col+1] <= 0)pseudomoves.push_back(push(row,col,row-2,col+1));
                if (row < 7 && col < 6 && board[row+1][col+2] <= 0)pseudomoves.push_back(push(row,col,row+1,col+2));
                if (row < 6 && col < 7 && board[row+2][col+1] <= 0)pseudomoves.push_back(push(row,col,row+2,col+1));
                if (row < 6 && col > 0 && board[row+2][col-1] <= 0)pseudomoves.push_back(push(row,col,row+2,col-1));
                if (row < 7 && col > 1 && board[row+1][col-2] <= 0)pseudomoves.push_back(push(row,col,row+1,col-2));
                if (row > 1 && col > 0 && board[row-2][col-1] <= 0)pseudomoves.push_back(push(row,col,row-2,col-1));
                if (row > 0 && col > 1 && board[row-1][col-2] <= 0)pseudomoves.push_back(push(row,col,row-1,col-2));
            }
            else if (board[row][col] == 2){
                a = row;
                b = col;
                if (a !=  0 && b != 0){
                    for (;;){
                        a-=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a !=  0 && b != 7){
                    for (;;){
                        a-=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));

                    }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 7){
                    for (;;){
                        a+=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 0){
                    for (;;){
                        a+=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
        }
            else if (board[row][col] == 6){
                a = row;
                b = col;
                if (a !=  0 && b != 0){
                    for (;;){
                        a-=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a !=  0 && b != 7){
                    for (;;){
                        a-=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));

                    }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 7){
                    for (;;){
                        a+=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 0){
                    for (;;){
                        a+=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a != 0){
                    for (;;){
                        a-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a!=7){
                    for(;;){
                        a+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (b!= 0){
                    for(;;){
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a  =row;
                b = col;
                if (b != 7){
                    for(;;){
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }

            }
            else if (board[row][col] == 10){
                if (row != 7 && board[row+1][col] <= 0)pseudomoves.push_back(push(row,col,row+1,col));
                if (row != 0 && board[row-1][col] <= 0)pseudomoves.push_back(push(row,col,row-1,col));
                if (col != 7 && board[row][col+1] <= 0)pseudomoves.push_back(push(row,col,row,col+1));
                if (col != 0 && board[row][col-1] <= 0)pseudomoves.push_back(push(row,col,row,col-1));
                if(row != 0 && col!= 0 && board[row-1][col-1] <= 0)pseudomoves.push_back(push(row,col,row-1,col-1));
                if(row != 0 && col!= 7 && board[row-1][col+1] <= 0)pseudomoves.push_back(push(row,col,row-1,col+1));
                if(row != 7 && col!= 0 && board[row+1][col-1] <= 0)pseudomoves.push_back(push(row,col,row+1,col-1));
                if(row != 7 && col!= 7 && board[row+1][col+1] <= 0)pseudomoves.push_back(push(row,col,row+1,col+1));
            }
        }//col loop
    }//row loop
    for (long unsigned int i = 0; i < pseudomoves.size(); i++){
        original = perform(pseudomoves[i]);
        if (check_w() == false) legal_moves.push_back(pseudomoves[i]);
        undomove(original,pseudomoves[i]);
    }
    return legal_moves;
}

int main(){
vector<vector<int>> legal_moves = generate_moves_w();
for (unsigned long int i = 0;i < legal_moves.size();i++) cout << legal_moves[i][0] << " " <<  legal_moves[i][1] << " " <<  legal_moves[i][2] << " " <<  legal_moves[i][3] << endl;
return 0;
}

MY LOGIC BEHIND GENERATING MOVES FOR EACH PIECE

• Pawn: A pawn has only a few conditions, so i didn't use any loops. Just hard code. I dont generate any moves for the pawn if the row in the loop is 7. Because it cannot move front. If it can however. I check whether board[row+1][col] is 0. If yes then i add it to pseudomoves by performing this function pseudomoves.push_back(push(row,col,row-1,col));. This statement is applicable to all. The first two arguments are co-ordinates of the initial position. Second two are co-ordinates of the desired position. For pawn i also check whether an enemy piece is available diagonally.

• Bishop: The moves of the bishop is done simply by using ** 4 loops ** Each loop for a direction it can move. Let's say i want to generate its moves top left. That means rows decreasing and col decreasing. I enter an infinite loop in which at each iteration. The increment/decrement happens(according to the direction). If at the new position i find a 0. I add it to pseudomoves and continue. If i find my own piece or if an edge has been reached, I break out of the loop. Lastly if I find an opponent's piece, add it to pseudomoves and then break , as it counts as a possible position. This same logic applies for all directions.

• Rook:

Same logic as bishop

• Queen:

moves of rook + moves of bishop

• King: total 8 directions in which the king can move. If the position is empty or has an opponents piece, add it to pseudomoves and check the next direction.

• Knight: Easiest out of all. At max 8 possible moves of the knight. Just increments and decrements in row and column. If the position is empty or has an opponents piece, add it to pseudomoves and check the next direction.

I am looking to improve this generator function and make it more efficient Any help is appreciated! perform():

int perform(vector<int> Move){
    int original;
    original = board[Move[2]][Move[3]];
    board[Move[2]][Move[3]] = board[Move[0]][Move[1]];
    board[Move[0]][Move[1]] = 0;
    return original;
}

undo():

void undomove(int original,vector<int> Move){
    board[Move[0]][Move[1]] = board[Move[2]][Move[3]];
    board[Move[2]][Move[3]] = original;
}

the board array:

int board[8][8] = {
  {-5,-3,-2,-6,-10,-2,-3,-5},
  {-1,-1,-1,-1,-1,-1,-1,-1},
  {0,0,0,0,-6,0,0,0},
  {0,0,0,0,5,0,0,0},
  {0,0,0,0,0,1,0,0},
  {0,0,0,0,0,0,0,0},
  {1,1,1,1,1,1,1,1},
  {5,3,2,6,10,2,3,5},
};

vector<vector<int>> generate_moves_w(){
    vector<vector<int>> pseudomoves,legal_moves;
    vector<int> move;
    int original,a,b;
for(int row = 0; row < 8; row++){
        for(int col = 0;col < 8;col++){
            if (!board[row][col]) continue;
//////////////////PAWN MOVES//////////////////////////////////////////
            if (board[row][col] == 1 && row != 0){
                if (row == 6 && board[row-1][col] == 0 && board[row-2][col] == 0)
                    pseudomoves.push_back(push(row,col,row-2,col));
                if (board[row-1][col] == 0)
                    pseudomoves.push_back(push(row,col,row-1,col));
                if (col != 0 && board[row-1][col-1] < 0)
                    pseudomoves.push_back(push(row,col,row-1,col-1));
                if (col != 7 && board[row-1][col+1] < 0)
                    pseudomoves.push_back(push(row,col,row-1,col+1));
            }
/////////////////////ROOK MOVES/////////////////////
            else if (board[row][col] == 5){
                a = row;
                b = col;
                if (a != 0){
                    for (;;){
                        a-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a!=7){
                    for(;;){
                        a+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (b!= 0){
                    for(;;){
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a  =row;
                b = col;
                if (b != 7){
                    for(;;){
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }

            }
///////////////KNIGHT MOVES////////////////////////////////////
            else if (board[row][col] == 3){
                if (row > 0 && col < 6 && board[row-1][col+2] <= 0)pseudomoves.push_back(push(row,col,row-1,col+2));
                if (row > 1 && col < 7 && board[row-2][col+1] <= 0)pseudomoves.push_back(push(row,col,row-2,col+1));
                if (row < 7 && col < 6 && board[row+1][col+2] <= 0)pseudomoves.push_back(push(row,col,row+1,col+2));
                if (row < 6 && col < 7 && board[row+2][col+1] <= 0)pseudomoves.push_back(push(row,col,row+2,col+1));
                if (row < 6 && col > 0 && board[row+2][col-1] <= 0)pseudomoves.push_back(push(row,col,row+2,col-1));
                if (row < 7 && col > 1 && board[row+1][col-2] <= 0)pseudomoves.push_back(push(row,col,row+1,col-2));
                if (row > 1 && col > 0 && board[row-2][col-1] <= 0)pseudomoves.push_back(push(row,col,row-2,col-1));
                if (row > 0 && col > 1 && board[row-1][col-2] <= 0)pseudomoves.push_back(push(row,col,row-1,col-2));
            }
////////////////////BISHOP MOVES///////////////////////
            else if (board[row][col] == 2){
                a = row;
                b = col;
                if (a !=  0 && b != 0){
                    for (;;){
                        a-=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a !=  0 && b != 7){
                    for (;;){
                        a-=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));

                    }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 7){
                    for (;;){
                        a+=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 0){
                    for (;;){
                        a+=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
        }
//////////////////// QUEEN MOVES /////////////////////////////////
            else if (board[row][col] == 6){
                a = row;
                b = col;
                if (a !=  0 && b != 0){
                    for (;;){
                        a-=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a !=  0 && b != 7){
                    for (;;){
                        a-=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));

                    }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 7){
                    for (;;){
                        a+=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 0){
                    for (;;){
                        a+=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a != 0){
                    for (;;){
                        a-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a!=7){
                    for(;;){
                        a+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (b!= 0){
                    for(;;){
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a  =row;
                b = col;
                if (b != 7){
                    for(;;){
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }

            }
////////////////////KING MOVES///////////////////////
            else if (board[row][col] == 10){
                if (row != 7 && board[row+1][col] <= 0)pseudomoves.push_back(push(row,col,row+1,col));
                if (row != 0 && board[row-1][col] <= 0)pseudomoves.push_back(push(row,col,row-1,col));
                if (col != 7 && board[row][col+1] <= 0)pseudomoves.push_back(push(row,col,row,col+1));
                if (col != 0 && board[row][col-1] <= 0)pseudomoves.push_back(push(row,col,row,col-1));
                if(row != 0 && col!= 0 && board[row-1][col-1] <= 0)pseudomoves.push_back(push(row,col,row-1,col-1));
                if(row != 0 && col!= 7 && board[row-1][col+1] <= 0)pseudomoves.push_back(push(row,col,row-1,col+1));
                if(row != 7 && col!= 0 && board[row+1][col-1] <= 0)pseudomoves.push_back(push(row,col,row+1,col-1));
                if(row != 7 && col!= 7 && board[row+1][col+1] <= 0)pseudomoves.push_back(push(row,col,row+1,col+1));
            }
        }//col loop
    }//row loop
    for (long unsigned int i = 0; i < pseudomoves.size(); i++){
        original = perform(pseudomoves[i]);
        if (check_w() == false) legal_moves.push_back(pseudomoves[i]);
        undomove(original,pseudomoves[i]);
    }
    return legal_moves;
}

Here is the push() function i have used in the code.

vector<int> push(int row,int col,int desrow,int descol){
    vector<int> move;
    move.push_back(row);
    move.push_back(col);
    move.push_back(desrow);
    move.push_back(descol);
    return move;
}

Here is check_w()

bool check_w(){
int row;
    int col;
    bool found = false;
    for (int i = 0; i < 8; i++){
        for (int j = 0;j < 8;j++){
            if(board[i][j] == 10){
                row = i;
                col = j;
                found = true;
            }
        }
    }
    if (found == false){
        cout << "There is no white king on the board " << endl;
        return false;
    }
    if (row != 0 && col != 0 && board[row-1][col-1] == -1) return true;
    if (row != 0 && col != 7 && board[row-1][col+1] == -1) return true;
    int a;
    int b;
    a = row;
    if (row != 7){
        for (;;){
            a+=1;
            if(board[a][col] == -5 || board[a][col] == -6) return true;
            if (a == 7 || board[a][col] != 0) break;
        }
    }
    a = row;
    if (row != 0){
        for (;;){
            a-=1;
            if(board[a][col] == -5 || board[a][col] == -6) return true;
            if (a == 0 || board[a][col] != 0) break;
        }
    }
    b = col;
    if (col != 0){
        for (;;){
            b-=1;
            if (board[row][b] == -6 or board[row][b] == -5) return true;
            if(b == 0 || board[row][b] != 0) break;
        }
    }
    b = col;
    if (col != 7){
        for (;;){
            b+=1;
            if (board[row][b] == -6 or board[row][b] == -5) return true;
            if(b == 7 || board[row][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 0 && b != 0){
        for (;;){
            a-=1;
            b-=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 0  || a == 0 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 0 && b != 7){
        for (;;){
            a-=1;
            b+=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 7  || a == 0 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 7 && b != 0){
        for (;;){
            a+=1;
            b-=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 0  || a == 7 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 7 && b != 7){
        for (;;){
            a+=1;
            b+=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 7  || a == 7 || board[a][b] != 0) break;
        }
    }
    if (row > 0 && col < 6 && board[row-1][col+2] == -3)return true;
    if (row > 1 && col < 7 && board[row-2][col+1] == -3)return true;
    if (row < 7 && col < 6 && board[row+1][col+2] == -3)return true;
    if (row < 6 && col < 7 && board[row+2][col+1] == -3)return true;
    if (row < 6 && col > 0 && board[row+2][col-1] == -3)return true;
    if (row < 7 && col > 1 && board[row+1][col-2] == -3)return true;
    if (row > 1 && col > 0 && board[row-2][col-1] == -3)return true;
    if (row > 1 && col > 0 && board[row-2][col-1] == -3)return true;
    if (row != 7 && board[row+1][col] == 10) return true;
    if (row != 0 && board[row-1][col] == 10) return true;
    if (col != 7 && board[row][col+1] == 10) return true;
    if (col != 0 && board[row][col-1] == 10) return true;
    if (row != 0 && col != 0 && board[row-1][col-1] == 10) return true;
    if (row != 0 && col != 7 && board[row-1][col+1] == 10) return true;
    if (row != 7 && col != 0 && board[row+1][col-1] == 10) return true;
    if (row != 7 && col != 0 && board[row+1][col+1] == 10) return true;
    return false;
}

Please mention if i forgot to provide any function :)

I am looking to improve this generator function and make it more efficient Any help is appreciated!

#include <iostream>
#include <vector>

using std::cout;
using std::cin;
using std::endl;
using std::vector;
int board[8][8] = {
  {-5,-3,-2,-6,-10,-2,-3,-5},
  {-1,-1,-1,-1,-1,-1,-1,-1},
  {0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0},
  {1,1,1,1,1,1,1,1},
  {5,3,2,6,10,2,3,5},
};
bool check_w(){
    int row;
    int col;
    bool found = false;
    for (int i = 0; i < 8; i++){
        for (int j = 0;j < 8;j++){
            if(board[i][j] == 10){
                row = i;
                col = j;
                found = true;
            }
        }
    }
    if (found == false){
        cout << "There is no white king on the board " << endl;
        return false;
    }
    if (row != 0 && col != 0 && board[row-1][col-1] == -1) return true;
    if (row != 0 && col != 7 && board[row-1][col+1] == -1) return true;
    int a;
    int b;
    a = row;
    if (row != 7){
        for (;;){
            a+=1;
            if(board[a][col] == -5 || board[a][col] == -6) return true;
            if (a == 7 || board[a][col] != 0) break;
        }
    }
    a = row;
    if (row != 0){
        for (;;){
            a-=1;
            if(board[a][col] == -5 || board[a][col] == -6) return true;
            if (a == 0 || board[a][col] != 0) break;
        }
    }
    b = col;
    if (col != 0){
        for (;;){
            b-=1;
            if (board[row][b] == -6 or board[row][b] == -5) return true;
            if(b == 0 || board[row][b] != 0) break;
        }
    }
    b = col;
    if (col != 7){
        for (;;){
            b+=1;
            if (board[row][b] == -6 or board[row][b] == -5) return true;
            if(b == 7 || board[row][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 0 && b != 0){
        for (;;){
            a-=1;
            b-=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 0  || a == 0 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 0 && b != 7){
        for (;;){
            a-=1;
            b+=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 7  || a == 0 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 7 && b != 0){
        for (;;){
            a+=1;
            b-=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 0  || a == 7 || board[a][b] != 0) break;
        }
    }
    a = row;
    b = col;
    if (a != 7 && b != 7){
        for (;;){
            a+=1;
            b+=1;
            if (board[a][b] == -6 or board[a][b] == -2) return true;
            if(b == 7  || a == 7 || board[a][b] != 0) break;
        }
    }
    if (row > 0 && col < 6 && board[row-1][col+2] == -3)return true;
    if (row > 1 && col < 7 && board[row-2][col+1] == -3)return true;
    if (row < 7 && col < 6 && board[row+1][col+2] == -3)return true;
    if (row < 6 && col < 7 && board[row+2][col+1] == -3)return true;
    if (row < 6 && col > 0 && board[row+2][col-1] == -3)return true;
    if (row < 7 && col > 1 && board[row+1][col-2] == -3)return true;
    if (row > 1 && col > 0 && board[row-2][col-1] == -3)return true;
    if (row > 1 && col > 0 && board[row-2][col-1] == -3)return true;
    if (row != 7 && board[row+1][col] == 10) return true;
    if (row != 0 && board[row-1][col] == 10) return true;
    if (col != 7 && board[row][col+1] == 10) return true;
    if (col != 0 && board[row][col-1] == 10) return true;
    if (row != 0 && col != 0 && board[row-1][col-1] == 10) return true;
    if (row != 0 && col != 7 && board[row-1][col+1] == 10) return true;
    if (row != 7 && col != 0 && board[row+1][col-1] == 10) return true;
    if (row != 7 && col != 0 && board[row+1][col+1] == 10) return true;
    return false;
}

vector<int> push(int row,int col,int desrow,int descol){
    vector<int> move;
    move.push_back(row);
    move.push_back(col);
    move.push_back(desrow);
    move.push_back(descol);
    return move;
}

void undomove(int original,vector<int> Move){
    board[Move[0]][Move[1]] = board[Move[2]][Move[3]];
    board[Move[2]][Move[3]] = original;
}

int perform(vector<int> Move){
    int original;
    original = board[Move[2]][Move[3]];
    board[Move[2]][Move[3]] = board[Move[0]][Move[1]];
    board[Move[0]][Move[1]] = 0;
    return original;
}

vector<vector<int>> generate_moves_w(){
    vector<vector<int>> pseudomoves,legal_moves;
    vector<int> move;
    int original,a,b;
    for(int row = 0; row < 8; row++){
        for(int col = 0;col < 8;col++){
            if (!board[row][col]) continue;
            if (board[row][col] == 1 && row != 0){
                if (row == 6 && board[row-1][col] == 0 && board[row-2][col] == 0)
                    pseudomoves.push_back(push(row,col,row-2,col));
                if (board[row-1][col] == 0)
                    pseudomoves.push_back(push(row,col,row-1,col));
                if (col != 0 && board[row-1][col-1] < 0)
                    pseudomoves.push_back(push(row,col,row-1,col-1));
                if (col != 7 && board[row-1][col+1] < 0)
                    pseudomoves.push_back(push(row,col,row-1,col+1));
            }
            else if (board[row][col] == 5){
                a = row;
                b = col;
                if (a != 0){
                    for (;;){
                        a-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a!=7){
                    for(;;){
                        a+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (b!= 0){
                    for(;;){
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a  =row;
                b = col;
                if (b != 7){
                    for(;;){
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }

            }
            else if (board[row][col] == 3){
                if (row > 0 && col < 6 && board[row-1][col+2] <= 0)pseudomoves.push_back(push(row,col,row-1,col+2));
                if (row > 1 && col < 7 && board[row-2][col+1] <= 0)pseudomoves.push_back(push(row,col,row-2,col+1));
                if (row < 7 && col < 6 && board[row+1][col+2] <= 0)pseudomoves.push_back(push(row,col,row+1,col+2));
                if (row < 6 && col < 7 && board[row+2][col+1] <= 0)pseudomoves.push_back(push(row,col,row+2,col+1));
                if (row < 6 && col > 0 && board[row+2][col-1] <= 0)pseudomoves.push_back(push(row,col,row+2,col-1));
                if (row < 7 && col > 1 && board[row+1][col-2] <= 0)pseudomoves.push_back(push(row,col,row+1,col-2));
                if (row > 1 && col > 0 && board[row-2][col-1] <= 0)pseudomoves.push_back(push(row,col,row-2,col-1));
                if (row > 0 && col > 1 && board[row-1][col-2] <= 0)pseudomoves.push_back(push(row,col,row-1,col-2));
            }
            else if (board[row][col] == 2){
                a = row;
                b = col;
                if (a !=  0 && b != 0){
                    for (;;){
                        a-=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a !=  0 && b != 7){
                    for (;;){
                        a-=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));

                    }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 7){
                    for (;;){
                        a+=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 0){
                    for (;;){
                        a+=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
        }
            else if (board[row][col] == 6){
                a = row;
                b = col;
                if (a !=  0 && b != 0){
                    for (;;){
                        a-=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a !=  0 && b != 7){
                    for (;;){
                        a-=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));

                    }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 7){
                    for (;;){
                        a+=1;
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a !=  7 && b != 0){
                    for (;;){
                        a+=1;
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b])pseudomoves.push_back(push(row,col,a,b));
                }
                }
                a = row;
                b = col;
                if (a != 0){
                    for (;;){
                        a-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (a!=7){
                    for(;;){
                        a+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || a == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a = row;
                b = col;
                if (b!= 0){
                    for(;;){
                        b-=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 0){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }
                a  =row;
                b = col;
                if (b != 7){
                    for(;;){
                        b+=1;
                        if (board[a][b] > 0) break;
                        if (board[a][b] < 0 || b == 7){
                            pseudomoves.push_back(push(row,col,a,b));
                            break;
                        }
                        if(!board[a][b]) pseudomoves.push_back(push(row,col,a,b));
                    }
                }

            }
            else if (board[row][col] == 10){
                if (row != 7 && board[row+1][col] <= 0)pseudomoves.push_back(push(row,col,row+1,col));
                if (row != 0 && board[row-1][col] <= 0)pseudomoves.push_back(push(row,col,row-1,col));
                if (col != 7 && board[row][col+1] <= 0)pseudomoves.push_back(push(row,col,row,col+1));
                if (col != 0 && board[row][col-1] <= 0)pseudomoves.push_back(push(row,col,row,col-1));
                if(row != 0 && col!= 0 && board[row-1][col-1] <= 0)pseudomoves.push_back(push(row,col,row-1,col-1));
                if(row != 0 && col!= 7 && board[row-1][col+1] <= 0)pseudomoves.push_back(push(row,col,row-1,col+1));
                if(row != 7 && col!= 0 && board[row+1][col-1] <= 0)pseudomoves.push_back(push(row,col,row+1,col-1));
                if(row != 7 && col!= 7 && board[row+1][col+1] <= 0)pseudomoves.push_back(push(row,col,row+1,col+1));
            }
        }//col loop
    }//row loop
    for (long unsigned int i = 0; i < pseudomoves.size(); i++){
        original = perform(pseudomoves[i]);
        if (check_w() == false) legal_moves.push_back(pseudomoves[i]);
        undomove(original,pseudomoves[i]);
    }
    return legal_moves;
}

int main(){
vector<vector<int>> legal_moves = generate_moves_w();
for (unsigned long int i = 0;i < legal_moves.size();i++) cout << legalmoves[i][0] << " " <<  legalmoves[i][1] << " " <<  legalmoves[i][2] << " " <<  legalmoves[i][3] << endl;
return 0;
}

The board is represented by an 8x8 integer array and the pieces are represented with numbers. Black pieces are negative of the same values white pieces use.

• pawn - 1
• bishop - 2
• rook - 5
• knight - 3
• queen - 6
• king - 10

A 0 in a place means that the position is empty. No piece is on it.

I have not added pawn promotion,en passant, and castle.

This is how the generator function works:

There are two main loops, outer loop for iterating through each row, inner loop for iterating through each column in each row. When I start iterating, if I find a 0, I skip the iteration. Hence, if(!board[row][col]) continue;

If i do find piece, a set of if statements check which piece it is, and accordingly add a vector of a possible move in the format [initial row, initial column, desired row,desired column]

After I generate all the moves, that means after it exits the loops, i need to iterate through all of them once again to validate them. Because if a piece was protecting a king from a check, it cannot be moved. I use the functions i have defined, which are perform() and undomove() to perform each move in the vector, add it to a new vector called legal_moves only IF the function check() returns false. this process returns a set of fully legal moves. However i wish to optimize it as i can perform this well over 50,000 times in a chess engine