How do I store a function to a variable?

Question

I think they are called functors? (it\'s been a while)

Basically, I want to store a pointer to a function in a variable, so I can specify what function I want to use

Answer 1

From C++11 you can use std::function to store functions. To store function you use it as follsonig:

std::function<return type(parameter type(s))>

as an example here it is:

#include 
#include 

int fact (int a) {
    return a > 1 ? fact (a - 1) * n : 1;
}

int pow (int b, int p) {
    return p > 1 ? pow (b, p - 1) * b : b;
}

int main (void) {
    std::function factorial = fact;
    std::function power = pow;

    // usage
    factorial (5);
    power (2, 5);
}