I started learning c++ and the first exercise was to create a small program to add two numbers. No more requirements. I did this and put a small validate the user input. I am sure that it could be much better written, so I appreciate all the critics and suggestions.

#include <iostream>
using namespace std;

int x; 
int sum = 0;
int i = 0;

int addTwoNumbers()
{
    while(i<2)
    {
        cin >> x;
        if(cin.fail())
        {
           cout << "Error! Invalid Input" << endl;
           cin.clear();
           cin.ignore(256,'\n');
        }
        else{
             sum += x;
             i++;
        }
   }
return sum;
}
int main()
{
    cout << "Enter two integers" << endl;
    return sum = addTwoNumbers();
}

Following the suggestion, I did some research and got why 'using namespace lib' is bad practice.

For example: If I have two libs and they have the same method, it would generate a conflict. So it would be better to use foo::method and bar::method

I updated the code to this:

#include <iostream>

int x;
int sum = 0;
int i = 0;

int addTwoNumbers()
{
    while(i<2)
    {
        std::cin >> x;
        if(std::cin.fail())
        {
           std::cout << "Error! Invalid Input" << std::endl;
           std::cin.clear();
           std::cin.ignore(256,'\n');
        }
        else
        {
             sum += x;
             i++;
        }
    }
    return sum;
}
int main()
{
    std::cout << "Enter two integers" << std::endl;
    return sum = addTwoNumbers();
}

I started learning C++ and the first exercise was to create a small program to add two numbers. No more requirements. I did this and put a small validate the user input. I am sure that it could be much better written, so I appreciate all the critics and suggestions.

#include <iostream>

int x;
int sum = 0;
int i = 0;

int addTwoNumbers()
{
    while(i<2)
    {
        std::cin >> x;
        if(std::cin.fail())
        {
           std::cout << "Error! Invalid Input" << std::endl;
           std::cin.clear();
           std::cin.ignore(256,'\n');
        }
        else
        {
             sum += x;
             i++;
        }
    }
    return sum;
}
int main()
{
    std::cout << "Enter two integers" << std::endl;
    return sum = addTwoNumbers();
}

I started learning c++ and the first exercise was to create a small program to add two numbers. No more requirements. I did this and put a small validate the user input. I am sure that it could be much better written, so I appreciate all the critics and suggestions.

#include <iostream>
using namespace std;

int x; 
int sum = 0;
int i = 0;

int addTwoNumbers()
{
    while(i<2)
    {
        cin >> x;
        if(cin.fail())
        {
           cout << "Error! Invalid Input" << endl;
           cin.clear();
           cin.ignore(256,'\n');
        }
        else{
             sum += x;
             i++;
        }
   }
return sum;
}
int main()
{
    cout << "Enter two integers" << endl;
    return sum = addTwoNumbers();
}

I started learning c++ and the first exercise was to create a small program to add two numbers. No more requirements. I did this and put a small validate the user input. I am sure that it could be much better written, so I appreciate all the critics and suggestions.

#include <iostream>
using namespace std;

int x; 
int sum = 0;
int i = 0;

int addTwoNumbers()
{
    while(i<2)
    {
        cin >> x;
        if(cin.fail())
        {
           cout << "Error! Invalid Input" << endl;
           cin.clear();
           cin.ignore(256,'\n');
        }
        else{
             sum += x;
             i++;
        }
   }
return sum;
}
int main()
{
    cout << "Enter two integers" << endl;
    return sum = addTwoNumbers();
}

Following the suggestion, I did some research and got why 'using namespace lib' is bad practice.

For example: If I have two libs and they have the same method, it would generate a conflict. So it would be better to use foo::method and bar::method

I updated the code to this:

#include <iostream>

int x;
int sum = 0;
int i = 0;

int addTwoNumbers()
{
    while(i<2)
    {
        std::cin >> x;
        if(std::cin.fail())
        {
           std::cout << "Error! Invalid Input" << std::endl;
           std::cin.clear();
           std::cin.ignore(256,'\n');
        }
        else
        {
             sum += x;
             i++;
        }
    }
    return sum;
}
int main()
{
    std::cout << "Enter two integers" << std::endl;
    return sum = addTwoNumbers();
}