C++之std::bind()用法

#include 
#include 
using namespace std;
//方式一：类使用bind
struct Foo{
	void print_sum(int n1, int n2, int n3){
		cout << "sum = " << n1 + n2 + n3 << endl;
	}
};

//方式二:函数使用bind
void print(int &n1, int &n2, int &n3){
	n1++;
	n2++;
	n3++;
}

int main(){

	//方式一：类实现
	Foo foo;
	auto callback = std::bind(&Foo::print_sum, &foo, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3);
	callback(5, 10, 15);//回调函数
//std::placeholders::_1...相当于占位符

	//方式二
	int a = 1, b = 2, c = 3;
	auto func2 = std::bind(print, a, b, std::ref(c)); //引用传参
	func2();
	cout <<"a = " << a << endl;
	cout <<"b = " << b << endl;
	cout <<"c = " << c << endl; 
}