C++ 输入输出运算符重载

类的输入输出运算符重载必须使用友元函数

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <math.h>
#include <vector>
#include <sstream>
#include <list>
#include <algorithm>
#include <time.h>
//头文件引用的较多,有一些和本程序无关

using namespace std;

class Test
{
public:
int a;
int b;
Test():a(0),b(0){}
Test(int a, int b):a(a),b(b){}
//重载输入输出运算符，只能用友元函数
friend ostream &operator<<(ostream &os, const Test &T);
friend istream &operator>>(istream &is, Test &T);
};

ostream &operator<<(ostream &os, const Test &T)
{
os << "a = " << T.a << endl;
os << "b = " << T.b << endl;

return os;
}

istream &operator>>(istream &is, Test &T)
{
is >> T.a >> T.b;
return is;
}

int main(int argc, char *argv[])
{
Test t(1, 2);
cout << t << endl;

cout << "请输入a和b的值,以空格分隔:" << endl;
cin >> t;
cout << t << endl;

system("pause");
return 0;
}
运行结果: