Function Callbacks

std::function can store a callable and pass it to another function.

function_callbacks.cpp

#include <functional>
#include <iostream>

void repeat(int count, const std::function<void(int)>& callback) {
    for (int index = 1; index <= count; index++) {
        callback(index);
    }
}

int main() {
    int count = ;
    int total = 0;

    repeat(count, [&total](int index) {
        total += index;
    });

    std::cout << "total=" << total << std::endl;
    std::cout << "done=" << count << std::endl;
    return 0;
}

#include <functional>
#include <iostream>

void repeat(int count, const std::function<void(int)>& callback) {
    for (int index = 1; index <= count; index++) {
        callback(index);
    }
}

int main() {
    int count = ;
    int total = 0;

    repeat(count, [&total](int index) {
        total += index;
    });

    std::cout << "total=" << total << std::endl;
    std::cout << "done=" << count << std::endl;
    return 0;
}

#include <functional>
#include <iostream>

void repeat(int count, const std::function<void(int)>& callback) {
    for (int index = 1; index <= count; index++) {
        callback(index);
    }
}

int main() {
    int count = ;
    int total = 0;

    repeat(count, [&total](int index) {
        total += index;
    });

    std::cout << "total=" << total << std::endl;
    std::cout << "done=" << count << std::endl;
    return 0;
}

callback A callback is a callable passed to another function so that function can call it later.