Back to slide -- Keyboard shortcut: 'u'                      io/copy-is-os.cc - Illustration of implicit stream conversion to a boolean value.Lecture 2 - slide 38 : 46
Program 1

#include <iostream>
#include <string>

using namespace std;

int main(){
  int i;

  while (cin >> i)   // cin is converted to 'a boolean value'
                     // via an implicit conversion operator
     cout << 2*i << " ";
  cout << "The End";

}