sizeof... operator
From cppreference.com
                    
                                        
                    
                    
                                                            
                    Queries the number of elements in a parameter pack.
| Contents | 
[edit] Syntax
| sizeof...(parameter_pack) | (since C++11) | ||||||||
Returns an object of type std::size_t.
[edit] Explanation
Returns the number of elements in a parameter pack.
[edit] Keywords
[edit] Example
Run this code
#include <iostream> template<class... Args> std::size_t f() { return sizeof...(Args); } int main() { std::cout << f<>() << '\n' << f<int>() << '\n' << f<char, int, double>() << '\n'; }
Output:
0 1 3


