第九周實驗報告（任務3）

程序頭部註釋開始
* 程序的版權和版本聲明部分
* Copyright (c) 2011, 煙臺大學計算機學院學生
* All rights reserved.
* 文件名稱： 分數類運算符重載  
* 作    者：     郭廣建                       
* 完成日期：  2012年    04  月  22    日
* 版 本 號：  1.0

源程序：

#include <iostream>   
  
using namespace std;  
  
class CFraction  
{  
private:  
    int nume;  // 分子
  
    int deno;  // 分母
  
 public: 
	 friend istream &operator >>(istream &input, CFraction &c2);

	 friend ostream &operator <<(ostream &output, CFraction &c2);

	 CFraction(int nu = 0, int de = 1);   //構造函數，初始化用

	 CFraction operator+(CFraction &c2);       //運算符的重載

	 CFraction operator-(CFraction &c2);

	 CFraction operator*(CFraction &c2);

	 CFraction operator/(CFraction &c2);

	 void Simplify();                             //化簡
};
int gcd(int de1,int de2);           //求最大公約數

istream &operator >>(istream &input, CFraction &c2)
{
	char c;

	while(1)
	{
		cout << "請按'分子/分母'順序輸入：" <<endl;

	    input >> c2.nume>> c >> c2.deno;

		if(c != '/')
		{
			continue;
		}
		if(c2.deno == 0)
		{
			continue;
		}
		else
		{
			break;
		}
	}
	return input;
}
ostream &operator <<(ostream &output, CFraction &c2)
{
	output <<'(' << c2.nume <<','<<c2.deno<<')';

		return output;
}
CFraction::CFraction(int nu , int de)
{
	if(de != 0)
	{
		nume = nu;

		deno = de;
	}
	else
	{
		cout << "輸入錯誤！" <<endl;

		exit(0);
	}
}
CFraction CFraction::operator+(CFraction &c2)
{
	CFraction c;

	int Max_r = gcd(deno, c2.deno);

	c.deno = (deno / Max_r) * (c2.deno / Max_r);

	c.nume = (nume * (c.deno / deno)) + (c2.nume * (c.deno / c2.deno));

	return c;
}

CFraction CFraction::operator-(CFraction &c2)
{
	CFraction c;

	int Max_r = gcd(deno, c2.deno);

	c.deno = (deno / Max_r) * (c2.deno / Max_r);

	c.nume = (nume * (c.deno / deno)) - (c2.nume * (c.deno / c2.deno));

	return c;
}



CFraction CFraction::operator*(CFraction &c2)
{
	return CFraction(nume * c2.nume , deno * c2.deno);
}

CFraction CFraction::operator/(CFraction &c2)
{
	return CFraction(nume * c2.deno , deno * c2.nume);
}

void CFraction::Simplify() 
{
	int m, n, r;

	m = abs(nume);

	n = abs(deno);

	r = gcd(m, n);

	deno /= r;

	nume /= r;

	if(deno < 0)
	{
		deno = -deno;

		nume = -nume;
	}
}

void main()
{

	CFraction c1, c2,c3;

	cin >> c1 >> c2;

	cout << "c1 =  " ;

	cout << c1 <<endl;

	cout << "c2 = " ;

	cout << c2 <<endl;

	c2.Simplify();

	cout << "c2化簡得：";

	cout << c2 <<endl;


	c3 = c1 + c2;

	cout << "c1 + c2 = " ;

	cout << c3 <<endl;

	c3 = c1 - c2;

	cout << "c1 - c2 = " ;

	cout << c3 <<endl;

	c3 = c1 * c2;

	cout << "c1 * c2 = " ;

	cout << c3 <<endl;

	c3 = c1 / c2;

	cout << "c1 / c2 = " ;

	cout << c3 <<endl;


	system("pause");
}





int gcd(int de1,int de2)
{
	int r;

	if(de1 < de2)
	{
		r = de1; de1 = de2; de2 = r;
	}

	while(r = de1 % de2)
	{
		de1 = de2;

		de2 = r;
	}

	return de2;
}

運行結果：

知識積累：

1. 通過對3種不同類的輸入、輸出符的重載，熟悉了運算符重載的很多細節的知識

2. 這幾週一直在做關於運算符重載的項目，從單目運算符、雙目運算符到輸入輸出運算符，感覺這些知識大體框架差不多，知識要注意裏面的細節問題，比如說重載時參數的知識，很值得注意

3. 不斷地用友元函數，對其掌握的已經比以前好多了，學習C++，就應該對裏面的很多知識重複使用，就自然而然的能夠熟練的掌握。