integer literal
From cppreference.com
                    
                                        
                    
                    
                                                            
                    
Contents | 
[edit] Syntax
| [0-9]+ type_suffix | (1) | ||||||||
| 0[0-7]+ type_suffix | (2) | ||||||||
| 0x[0-9a-f]+ type_suffix | (3) | ||||||||
[edit] Explanation
- Decimal notation
 - Octal notation
 - Hexadecimal notation
 
[edit] Types by suffix
- (no suffix)
 - int
 - u
 - unsigned int
 - l
 - long
 - ul
 - unsigned long
 - ll (since C++11)
 - long long
 - ull (since C++11)
 - unsigned long long
 - User defined (since C++11)
 - anything
 
[edit] Notes
- Letters in integer constants are case-insensitive.
 
[edit] Example
std::cout << 123 << '\n' << 0123 << '\n' << 0x123 << '\n' << 12345678901234567890UL << '\n' << -1u << '\n' << -1ull << '\n';
Output:
123 83 291 12345678901234567890 4294967295 18446744073709551615
(output from an x86_64 processor)