分数的计算，以(-3）/8+(-5）/(-6)为例

#include <iostream>
//#include <csting>

using namespace std;
class Fraction
{
public:
    Fraction(int=1,int=1);
    void output();
    Fraction operator+(Fraction &p);
private:
    int numerator;
    int denominator;
    int gcd(int,int);
};
int Fraction::gcd(int m,int n)
{
    int r;
    if(m<n){r=m;m=n;n=r;}
    while(m%n!=0)
    {
        r=m%n;
        m=n;
        n=r;
    }
/*    while(r=m%n)
    {
        m=n;
        n=r;
    }*/
    return n;
}
Fraction ::Fraction(int nume,int deno)
{
    numerator=nume;denominator=deno;
}
void Fraction::output()
{
    if(numerator*denominator<0)
        cout<<"-";
    if(numerator<0)
        cout<<-numerator;
    else
    cout<<numerator;
    cout<<"/";
    if(denominator<0)
        cout<<-denominator;
    else
    cout<<denominator;
}
Fraction Fraction::operator+(Fraction &p)
{
    int nume,deno;
    nume=numerator*p.denominator+denominator*p.numerator;
    deno=denominator*p.denominator;
    int num=gcd(nume,deno);
    return Fraction(nume/num,deno/num);
}

int main()
{
    Fraction f1(-3,8),f2(-5,-6),f3;
    f3=f1+f2;
    f3.output();
    return 0;
}