帮我写一个程序1． 定义一个有理数类Rational，包含分子和分母两个属性，为其重载四则运算和输入输出流，以使用cin和cout对Rational的对象进行输入和输出。

好的，下面是代码实现：

#include <iostream>
using namespace std;

class Rational {
public:
    Rational(int num = 0, int den = 1) : numerator(num), denominator(den) {}
    friend istream& operator>>(istream& in, Rational& r) {
        char slash;
        in >> r.numerator >> slash >> r.denominator;
        return in;
    }
    friend ostream& operator<<(ostream& out, const Rational& r) {
        out << r.numerator << '/' << r.denominator;
        return out;
    }
    friend Rational operator+(const Rational& a, const Rational& b) {
        return Rational(a.numerator*b.denominator + a.denominator*b.numerator, a.denominator*b.denominator);
    }
    friend Rational operator-(const Rational& a, const Rational& b) {
        return Rational(a.numerator*b.denominator - a.denominator*b.numerator, a.denominator*b.denominator);
    }
    friend Rational operator*(const Rational& a, const Rational& b) {
        return Rational(a.numerator*b.numerator, a.denominator*b.denominator);
    }
    friend Rational operator/(const Rational& a, const Rational& b) {
        return Rational(a.numerator*b.denominator, a.denominator*b.numerator);
    }
private:
    int numerator;
    int denominator;
};

int main() {
    Rational a, b;
    cout << "Please enter two rational numbers (format like 1/2):" << endl;
    cin >> a >> b;
    cout << a << " + " << b << " = " << a+b << endl;
    cout << a << " - " << b << " = " << a-b << endl;
    cout << a << " * " << b << " = " << a*b << endl;
    cout << a << " / " << b << " = " << a/b << endl;
    return 0;
}