how to pass function as a parameter in c 2b 2b

1#include <bits/stdc++.h> 
2using namespace std;
3
4int add(int x, int y){return x+y;}
5int sub(int x, int y){return x-y;}
6int operation (int x, int y,int (*function)(int,int)){return function(x,y);}
7int operation2(int x, int y,std::function<int(int, int)> function){return function(x,y);}
8
9int main()
10{
11    std::cout <<"Values 1 & 3. Pointer function: Add:"<<operation (1,3,&add)<<" Sub:"<<operation (1,3,&sub) << std::endl;
12    std::cout <<"Values 1 & 3. std::function   : Add:"<<operation2(1,3,&add)<<" Sub:"<<operation2(1,3,&sub) << std::endl;
13}