C + + input, output operator overloading

C + + can use stream extraction operators >> and stream insert operators << to enter and output built-in data types. We can overload the stream extraction operator and the stream insert operator to manipulate user-defined data types such as objects.

Here, it is important to declare the operator overload function as a friend function of the class, so that we can directly invoke the function without creating the object.
The following example shows how to overload the extract operator >> and insert operator <<.

#include <iostream>using namespace std;class Person{public:    Person(const char *str) : name(str){}        int GetAge(){        return this->age;    }        /* 声明为类的友元函数 */    friend ostream& operator<<(ostream& output, Person &p){        output << p.name << endl;        return output;    }        friend istream& operator>>(istream& input, Person &p){        input >> p.age;        return input;    }    private:    const char *name;    int age;};int main(){    Person p("Tom");        /* 重载输出名字 */    cout << p;        /* 重载输入年龄 */    cin >> p;        /* 输出年龄 */    cout << p.GetAge() << endl;        return 0;}

C + + input, output operator overloading