C++程序设计(第2版)课后习题答案第11章

11.9  定义分数类Rational......

#include<iostream.h>
#include<stdlib.h>
class Rational{
private:
    int fm,fz;
    int getZdgys(int a,int b);
public:
    Rational(){
        fm=1;fz=0;
    }
    Rational(int a,int b);
    friend Rational Add(Rational r1,Rational r2);
    friend Rational Sub(Rational r1,Rational r2);
    void Print1();
    void Print2();
};

Rational::Rational(int fm1,int fz1)
{
    int t=getZdgys(fm1,fz1);
    fm=fm1/t;
    fz=fz1/t;
}

void Rational::Print1()
{
    cout<<fz<<"/"<<fm<<endl;
}

void Rational::Print2()
{
    cout<<(double(fz)/fm)<<endl;
}

int Rational::getZdgys(int a,int b)
{
    int t;
    while(t=a%b)
    {
        a=b;
        b=t;
    }
    return b;
}

Rational Add(Rational r1,Rational r2)
{
    int m= r1.fm*r2.fm;
    int n= r1.fz*r2.fm+r1.fm*r2.fz;
    Rational result(m,n);
    return result;
}
Rational Sub(Rational r1,Rational r2)
{
    int m= r1.fm*r2.fm;
    int n= r1.fz*r2.fm-r1.fm*r2.fz;
    Rational result(m,n);
    return result;
}
void main()
{
    Rational a(24,12);
    Rational b(6,1);
    Rational result;
    result=Add(a,b);
    result.Print1();
    
    result=Sub(a,b);
    result.Print1();
}