左移运算符重载

左移运算符重载

• 作用：可以输出自定义类型

代码示例：
#include <iostream>
using namespace std;
//左移运算符重载
class Person
{
   
       friend ostream & operator<<(ostream &cout, Person &p);
public:
       Person(int a, int b)
       {
   
              m_A = a;
              m_B = b;
       }
private:
       
       //利用成员函数重载左运算符 p.operator<<(cout) 简化版本p<<cout
       //void operator<<(cout)
       //{
   
       // 
       //}
       int m_A;
       int m_B;
};
//只能利用全局函数重载左移运算符
ostream & operator<<(ostream &cout, Person &p)         //本质 operator<<(cout,p) 简化 cout<<p
{
   
       cout << "m_A=" << p.m_A << " m_B=" << p.m_B;
       return cout;
}
void test01()
{
   
       Person p(10,10);
       //p.m_A = 10;
       //p.m_B = 10;
       cout << p<<"hello world"<<endl;
}
int main()
{
   
       test01();
       return 0;
}

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

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