boolean literal in C++

The Boolean literals are the keywords true and false. 
```
#include <iostream>
 
int main()
{
  std::cout << std::boolalpha
            << true << '\n'
            << false << '\n'
            << std::noboolalpha
            << true << '\n'
            << false << '\n';
}
/*
Output:

true
false
1
0
*/
```