#include <functional>
#include <iostream>
struct Foo {
Foo(int num) : num_(num) {}
void print_add(int i) const { std::cout << num_+i << '\n'; }
int num_;
};
void print_num(int i)
{
std::cout << i << '\n';
}
struct PrintNum {
void operator()(int i) const
{
std::cout << i << '\n';
}
};
int main()
{
// store a free function
std::function<void(int)> f_display = print_num;
f_display(-9);
// store a lambda
std::function<void()> f_display_42 = []() { print_num(42); };
f_display_42();
// store the result of a call to std::bind
std::function<void()> f_display_31337 = std::bind(print_num, 31337);
f_display_31337();
// store a call to a member function
std::function<void(const Foo&, int)> f_add_display = &Foo::print_add;
const Foo foo(314159);
f_add_display(foo, 1);
// store a call to a member function and object
using std::placeholders::_1;
std::function<void(int)> f_add_display2= std::bind( &Foo::print_add, foo, _1 );
f_add_display2(2);
// store a call to a function object
std::function<void(int)> f_display_obj = PrintNum();
f_display_obj(18);
}