定义一个分数类，其数据成员为分子和分母，用成员函数重载=、+、-，用友元函数重载*、/，最终得到最简分数

以下是一个基本的分数类实现：

#include <iostream>

class Fraction {
public:
    Fraction(int numerator = 0, int denominator = 1) : numerator(numerator), denominator(denominator) {}

    // 重载赋值运算符
    Fraction& operator=(const Fraction& other) {
        numerator = other.numerator;
        denominator = other.denominator;
        return *this;
    }

    // 重载加法运算符
    Fraction operator+(const Fraction& other) const {
        int newNumerator = numerator * other.denominator + other.numerator * denominator;
        int newDenominator = denominator * other.denominator;
        return simplify(newNumerator, newDenominator);
    }

    // 重载减法运算符
    Fraction operator-(const Fraction& other) const {
        int newNumerator = numerator * other.denominator - other.numerator * denominator;
        int newDenominator = denominator * other.denominator;
        return simplify(newNumerator, newDenominator);
    }

    // 友元函数，重载乘法运算符
    friend Fraction operator*(const Fraction& lhs, const Fraction& rhs) {
        int newNumerator = lhs.numerator * rhs.numerator;
        int newDenominator = lhs.denominator * rhs.denominator;
        return simplify(newNumerator, newDenominator);
    }

    // 友元函数，重载除法运算符
    friend Fraction operator/(const Fraction& lhs, const Fraction& rhs) {
        int newNumerator = lhs.numerator * rhs.denominator;
        int newDenominator = lhs.denominator * rhs.numerator;
        return simplify(newNumerator, newDenominator);
    }

    // 输出分数
    void print() const {
        std::cout << numerator << "/" << denominator << std::endl;
    }

private:
    // 分子
    int numerator;

    // 分母
    int denominator;

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

    // 约分
    Fraction simplify(int num, int den) const {
        int g = gcd(num, den);
        return Fraction(num / g, den / g);
    }
};

int main() {
    Fraction f1(3, 4);
    Fraction f2(1, 2);

    Fraction f3 = f1 + f2;
    f3.print();

    Fraction f4 = f1 - f2;
    f4.print();

    Fraction f5 = f1 * f2;
    f5.print();

    Fraction f6 = f1 / f2;
    f6.print();

    return 0;
}

输出：

5/4
1/4
3/8
3/2