bool literal
From cppreference.com
                    
                                        
                    
                    
                                                            
                    [edit] Syntax
| true | (1) | ||||||||
| false | (2) | ||||||||
[edit] Explanation
- boolean 
true(value of 1) - boolean 
false(value of 0) 
[edit] Example
std::cout << std::boolalpha << true << '\n' << false << '\n' << std::noboolalpha << true << '\n' << false << '\n';
Output:
true false 1 0