C++ 輸入輸出運算符重載

類的輸入輸出運算符重載必須使用友元函數

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <math.h>
#include <vector>
#include <sstream>
#include <list>
#include <algorithm>
#include <time.h>
//頭檔案引用的較多,有一些和本程式無關

using namespace std;

class Test
{
public:
	int a;
	int b;
	Test():a(0),b(0){}
	Test(int a, int b):a(a),b(b){}
	//重載輸入輸出運算符，隻能用友元函數
	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 << "請輸入a和b的值,以空格分隔:" << endl;
	cin >> t;
	cout << t << endl;

	system("pause");
	return 0;
}
           

運作結果: