std::cin.clear() fails to restore input stream in a good state

Question

In order to test bool i/o, I tried to run this short program:

#include 

int main()
{
 while(true)
 {
  bool f;
  if (std::cin >> f)
   std         


        

Answer 1

Add this line after clearing cin:

std::cin.ignore();

This way, the stream ignores whatever is left on its buffer.

Answer 2

if (std::cin >> f) expects either a 0 or 1. And treats all other values as an I/0 error. Even if you enter '-' or 2, std::cin.ignore() is still needed.

If you want the program to enter only the values true or false, use the following statement instead of (std::cin >> f)

(std::cin >> boolalpha >> f)

Answer 3

Try to use following combo:

cin.ignore(INT_MAX, '\n'); // ignore all characters in the current line

cin.clear(); // restore 'good' flag

Using only cin.ignore() will discard only one character in the buffer.