设计一个分数类，将加减乘除运算符重载，加减用成员函数，乘除用友元

下面是一个设计分数类的示例代码，实现了加减乘除的运算符重载：

#include <iostream>
#include <cmath>

using namespace std;

class Fraction {
public:
    Fraction(int num, int den = 1) : numerator(num), denominator(den) {}
    Fraction operator+(const Fraction& rhs);
    Fraction operator-(const Fraction& rhs);
    friend Fraction operator*(const Fraction& lhs, const Fraction& rhs);
    friend Fraction operator/(const Fraction& lhs, const Fraction& rhs);
    void print();
private:
    int numerator;
    int denominator;
    void reduce();
};

Fraction Fraction::operator+(const Fraction& rhs) {
    int new_num = numerator * rhs.denominator + denominator * rhs.numerator;
    int new_den = denominator * rhs.denominator;
    return Fraction(new_num, new_den);
}

Fraction Fraction::operator-(const Fraction& rhs) {
    int new_num = numerator * rhs.denominator - denominator * rhs.numerator;
    int new_den = denominator * rhs.denominator;
    return Fraction(new_num, new_den);
}

Fraction operator*(const Fraction& lhs, const Fraction& rhs) {
    int new_num = lhs.numerator * rhs.numerator;
    int new_den = lhs.denominator * rhs.denominator;
    return Fraction(new_num, new_den);
}

Fraction operator/(const Fraction& lhs, const Fraction& rhs) {
    int new_num = lhs.numerator * rhs.denominator;
    int new_den = lhs.denominator * rhs.numerator;
    return Fraction(new_num, new_den);
}

void Fraction::print() {
    reduce();
    cout << numerator << "/" << denominator << endl;
}

void Fraction::reduce() {
    int gcd = abs(__gcd(numerator, denominator));
    numerator /= gcd;
    denominator /= gcd;
}

int main() {
    Fraction a(1, 2);
    Fraction b(3, 4);
    Fraction c = a + b;
    c.print(); // 输出 5/4
    c = a - b;
    c.print(); // 输出 -1/4
    c = a * b;
    c.print(); // 输出 3/8
    c = a / b;
    c.print(); // 输出 2/3
    return 0;
}

在上面的代码中，我们定义了一个分数类`Fraction`，其中`numerator`表示分子，`denominator`表示分母。构造函数可以接受一个分子和一个分母，如果只传入一个参数，则默认分母为1。`operator+`和`operator-`是成员函数，重载了加法和减法运算符。`operator*`和`operator/`是友元函数，重载了乘法和除法运算符。`print`函数用于输出分数，`reduce`函数用于化简分数。在`main`函数中，我们创建了两个分数`a`和`b`，然后对它们进行加减乘除运算，并输出结果。