设计分数类Fraction，成员数据包括分子Numerator和分母Denominator，类型都是int。 main函数已给定，提交时只需要提交main函数外的代码部分。 #include<iostream> using namespace std; //你提交的代码在这里 int main() { Fraction f1,f2,f3; cin>>f1>>f2; f3=f1+f2; cout<<f1<<" + "<<f2<<" = "<<f3<<endl; f3=f1-f2; cout<<f1<<" - "<<f2<<" = "<<f3<<endl; f3=f1*f2; cout<<f1<<" * "<<f2<<" = "<<f3<<endl; f3=f1/f2; cout<<f1<<" / "<<f2<<" = "<<f3<<endl; return 0; } Input 1行4个整数，前2个整数分别表示第一个分数的分子和分母；后2个整数分别表示第二个分数的分子和分母。分母保证不为0。 Output 按照样例输出格式输出。 Sample Input 1 1 2 3 4 Sample Output 1 1/2 + 3/4 = 5/4 1/2 - 3/4 = -1/4 1/2 * 3/4 = 3/8 1/2 / 3/4 = 2/3 Hint 分数的输出要求： （1）格式：整数/整数 （2）最简形式； （3）分子只能是正整数；

#include<iostream>
using namespace std;

int gcd(int a, int b) {  //辗转相除法求最大公约数
    return b == 0 ? a : gcd(b, a % b);
}

class Fraction {
private:
    int numerator, denominator;  //分子和分母
public:
    Fraction(int n = 0, int d = 1) {  //构造函数，默认为0/1
        numerator = n;
        denominator = d;
        simplify();  //构造时自动约分
    }
    friend istream& operator>>(istream& in, Fraction& f) {  //输入运算符重载
        in >> f.numerator >> f.denominator;
        f.simplify();  //读入时自动约分
        return in;
    }
    friend ostream& operator<<(ostream& out, const Fraction& f) {  //输出运算符重载
        out << f.numerator << '/' << f.denominator;
        return out;
    }
    Fraction operator+(const Fraction& f) const {  //加法运算符重载
        Fraction res(numerator * f.denominator + f.numerator * denominator, denominator * f.denominator);
        return res;
    }
    Fraction operator-(const Fraction& f) const {  //减法运算符重载
        Fraction res(numerator * f.denominator - f.numerator * denominator, denominator * f.denominator);
        return res;
    }
    Fraction operator*(const Fraction& f) const {  //乘法运算符重载
        Fraction res(numerator * f.numerator, denominator * f.denominator);
        return res;
    }
    Fraction operator/(const Fraction& f) const {  //除法运算符重载
        Fraction res(numerator * f.denominator, denominator * f.numerator);
        return res;
    }
    void simplify() {  //约分
        int g = gcd(numerator, denominator);
        numerator /= g;
        denominator /= g;
        if (denominator < 0) {  //保证分母为正
            numerator = -numerator;
            denominator = -denominator;
        }
    }
};

int main() {
    Fraction f1, f2, f3;
    cin >> f1 >> f2;
    f3 = f1 + f2;
    cout << f1 << " + " << f2 << " = " << f3 << endl;
    f3 = f1 - f2;
    cout << f1 << " - " << f2 << " = " << f3 << endl;
    f3 = f1 * f2;
    cout << f1 << " * " << f2 << " = " << f3 << endl;
    f3 = f1 / f2;
    cout << f1 << " / " << f2 << " = " << f3 << endl;
    return 0;
}