A small program that demonstrates the definition and usages of lambda expressions in C++.

LambdaSample.cpp

#include <functional>
#include <iostream>
#include <stdio.h>
using namespace std;

extern function<int(int, function<int(int)>)> g;

auto f = [](int n, function<int(int)> h)
{
    if (n >= 5) return n;
    cout << "h is some function " << h(4.0) << endl;
    auto func = [h](int m) { return m*h(m); };   
    return g(n + 1, func);
};

function<int(int, function<int(int)>)> g = [](int n, function<int(int)> h)
{
    if (n >= 5) return n;
    cout << "h is some function " << h(5.0) << endl;
    auto func = [h](int m) { return m*h(m); };   
    return f(n + 1, func);
};

int main()
{
    auto initial_function = [](int m) { return m*m; };
    f(1, initial_function);

    getchar();
    return 0; // Return value of the function is int so its better to use 0 rather than 0.0
}