左移运算符重载

1. 总结：重载左移运算符配合友元可以实现输出自定义数据类型

#include
using namespace std;

class Person {
private:
	int m_A;
	int m_B;
public:
	friend ostream& operator<<(ostream& out, Person& p);
	Person(int a, int b)
	{
		this->m_A = a; 
		this->m_B = b;
	}
	//成员函数实现不了 p<
	//void operactor <<(Person &p)
};

//全局函数实现左移重载
//ostream对象左移只能有一个
ostream& operator<<(ostream& out, Person& p) {  //ostream是输出流 out可以是任何变量，使用引用取别名
	out << "a:" << p.m_A << " b:" << p.m_B;
	return out;
}
void test() {
	Person p1(10, 20);
	cout << p1 << "hello world " << endl; //链式编程
}

int main()
{
	test();
	return 0;
}
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