std_invoke.org

C++ 17 std::invoke

source code from: https://en.cppreference.com/w/cpp/utility/functional/invoke

#include <iostream>
#include <functional>

using namespace std;

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()
{
	//invoke free function
	std::invoke(print_num, -9);
	
	//invoke a lambda
	std::invoke([]() {print_num(42); });
	
	//Invoke a member function
	const Foo foo(25);
	std::invoke(&Foo::print_add, foo, 1);
	
	//invoke (access) a data member
	cout << "num_: " << std::invoke(&Foo::num_, foo) << endl;
	
	//invoke a function object
	std::invoke(PrintNum(), 18);
	
	return 0;
}