My task is to enter in one row of data, 1 number tells how many elements the array will have, the next tells what elements they will be. Before entering data I do not know how big a 3-element or 300 array can be. Example
Input 5 3 6 5 7 8
Array1[5]={3,6,5,7,8}
If I press enter it initializes the next table Board2, like
Input 3 9 8 3
Array2[3]={9,8,3}
If he gets two enters, he will stop entering data. Can you help me with this?
You could try old school and allocate the array from dynamic memory after the capacity is read in:
int capacity = 0;
std::cin >> capacity;
int * array = new int[capacity];
for (int i = 0; i < capacity; ++i)
{
std::cin >> array[i];
}
//...
delete [] array;
std::cin function ignores whitespace; so the numbers can be space separated on one line or one number per line.You can use a std::istringstream and std::vector for that, eg:
std::string input;
std::getline(std::cin, input);
std::istringstream iss(input);
int n;
iss >> n;
std::vector<int> vec(n);
for(int i = 0; i < n; ++i) {
iss >> vec[i];
}
On the other hand, if you do use this approach, then you can omit the leading number altogether since std::vector can grow dynamically, so there is no eed to be explicit about the count of numbers in the input:
std::string input;
std::getline(std::cin, input);
std::istringstream iss(input);
int i;
std::vector<int> vec;
while (iss >> i) {
vec.push_back(i);
}
/* Alternatively:
std::vector<int> vec(
std::istream_iterator<int>(iss),
std::istream_iterator<int>()
);
*/
