Avoiding infinite loop when a char is enter in place of int

Question

I\'m doing a Banking System project and need to make sure that every input is valid(program has to be robust). If invalid input is given then user has to enter again.
Bu

Answer 1

Here is another approach that might help; first writing to std::string and then going over all elements in the string checking if they're digit. Using header for isdigit() and for std::atoi, although in c++11 you can use std::stoi if your compiler supports it.

If you write: 141.4123, the result will be 141 after converting (if you let the user type '.'), the result will be truncated because you convert to an int.

Working example:

int str_check(string& holder, int& x)
{
  bool all_digits = true; // we expect that all be digits.

  if (cin >> holder) {
    for(const auto& i : holder) {
      if (!isdigit(i) && i != '.') { // '.' will also pass the test.
        all_digits = false;
        break;
      }
    }
    if (all_digits) {
      x = atoi(holder.c_str()); // convert str to int using std::atoi
      return 1;
    }
    else
      return 0;
  }
}

int main()
{
  int x{};
  string holder{};
  while (1)
  {
    if (str_check(holder, x))
      cout << x << '\n';
  }

  return 0;
}