618.cpp

C++实训教程

/*
	618.cpp OperOver!Fraction.cpp
	分数的四则运算
	Written by Feng Rev.2004
*/
#include <iostream.h>

class Fraction;
long GCD(long a,long b);      //最大公约数Greatest common Dividor最大公约数
long LCM(long a,long b);		//最小公倍数Lowest common Multiple 最小公倍数
void Reduce(long &a,long &b); //   公约，化简
void DispOper(Fraction a,char c,Fraction b);
class Fraction
{
   long x,y;  //分数  x/y
 public:
	Fraction ()	{x=0;y=1;} //y must not =0
	Fraction(long a,long b=1)
	{
		if(b<0)	{a=-a; b=-b;}
		else if (b==0) b=1;
		x=a;y=b;
	}
	Fraction operator +(const Fraction&c);
	Fraction operator -(const Fraction&c);
	Fraction operator *(const Fraction&c);
	Fraction operator /(const Fraction&c);
	void Disp()	{	cout<<"("<<x<<"/"<<y<<") "; }
};

Fraction Fraction::operator+(const Fraction&c)
{
	long a,b;
	a = x*c.y + y*c.x; b =y*c.y;
	Reduce(a,b);
	return Fraction(a,b);
}

Fraction Fraction::operator -(const Fraction&c)
{
	long a,b;
	a = x*c.y - y*c.x; b =y*c.y;
	Reduce(a,b);
	return Fraction(a,b);
}

Fraction Fraction::operator *(const Fraction&c)
{
	long a,b;
	a = x*c.x ; b = y*c.y;
	Reduce(a,b);
	return Fraction(a,b);
}

Fraction Fraction::operator /(const Fraction&c)
{
	long a,b;
	a = x*c.y ; b = y*c.x;
	Reduce(a,b);
	return Fraction(a,b);
}

void DispOper(Fraction a,char c,Fraction b)
{
	a.Disp(); cout << c;
	b.Disp(); cout << " = ";
	switch (c)
	{
		case int('+'):  a=a+b; break;
		case int('-'):  a=a-b; break;
		case int('*'):  a=a*b; break;
		case int('/'):  a=a/b; break;
		default:   		 a=a+b; break;
	}
	a.Disp();
}


main()
{
	Fraction b1(3,4);
	Fraction b2(-5,6);
	Fraction b3;
	b3=b1+b2;
	b3.Disp(); cout <<endl;
	DispOper(b1,'+',b2); cout <<endl;

	b3=b1-b2;
	b3.Disp(); cout <<endl;
	DispOper(b1,'-',b2);cout <<endl;

	b3=b1*b2;
	b3.Disp(); cout <<endl;
	DispOper(b1,'*',b2); cout <<endl;

	b3=b1/b2;
	b3.Disp(); cout <<endl;
	DispOper(b1,'/',b2); cout <<endl;

	return 0;
}

long GCD(long a,long b)
{
	long t;
	if(a>b)	{t=a;a=b;b=t;}//swap to a<b
	while((t = (b%a)) != 0){b=a;a=t;}
	return a;
}

long LCM(long a,long b)
{return (a*b/GCD(a,b));	}

void Reduce(long &a,long &b)
{
	long gcd = GCD(a,b);
	a = a/gcd;
	b = b/gcd;
}

/*-
(-1/12)
(3/4) +(-5/6)  = (-1/12)
(19/12)
(3/4) -(-5/6)  = (19/12)
(-5/8)
(3/4) *(-5/6)  = (-5/8)
(-9/10)
(3/4) /(-5/6)  = (-9/10)

*/