std::function常见的5种用法

std::function常见的几种用法

运行结果：

代码示例：

#include<iostream>
#include<functional>
#include<string>
class FOO {
public:
	void operator()(int i) {
		std::cout << "print i=" << i << std::endl;
	}
	void print_add(int i) const { std::cout << "print i="<<i << std::endl; }
	void print_add_1() const { std::cout << "print i=10"<< std::endl; }
	int number=10;
};
void print(int number) {
	std::cout << "print number=" << number << std::endl;
}
int main() {

	//1.运算符重载
	FOO foo;
	foo(10);
	
	//2.访问类的成员函数
	std::function<void(FOO&,int i)>fun1 = &FOO::print_add;
	FOO foo_1;
	fun1(foo_1,10);
	
	//3.访问类的成员函数
	std::function<void(FOO&)>fun2 = &FOO::print_add_1;
	fun2(foo_1);
	
	//4.访问局部函数
	std::function<void(int)>fun3 = print;
	fun3(10);
	
	//5.访问成员变量
	std::function<int(FOO&)>fun4 = &FOO::number;
	std::cout<<"num="<<fun4(foo)<<std::endl;
	
	//6.访问Lambda表达式
	std::function<void(int)>fun5 = [=](int value){ std::cout << "print value=" << value << std::endl; };
	fun5(10);
	
	return 0;
}