Passing a 'Function' as a argument to another Function-C++

#include<iostream>
using namespace std;

int sum(int a,int b)
{
   return a+b;
}
void f2(int (*f)(int,int),int a,int b) //'*f' is a POINTER TO A FUNCTION whose RETURN TYPE is                                                           //'int' and arg type (int,int)  . Here, '*f' is FORMAL PARAMETER
{                                                                
  cout<<sum(a,b)<<endl;
}
int main()
{   int (*p1)(int,int)=&sum;          //Here, '*pf1' is ACTUAL PARAMETER
    f2(sum,10,20);                         //NAME OF A FUNCTION IS ITSELF A POINTER TO ITSELF
    f2(p1,20,79);
    return 0;

}