实现Java函数：如何在Java中实现有理数运算的函数？

在Java中实现有理数运算的函数，可以创建一个有理数类，并在该类中定义各种运算方法。下面是一个简单的有理数类的实现：

public class RationalNumber {
    private int numerator;
    private int denominator;

    public RationalNumber(int num, int denom) {
        numerator = num;
        denominator = denom;
    }

    public RationalNumber add(RationalNumber other) {
        int num = numerator * other.denominator + other.numerator * denominator;
        int denom = denominator * other.denominator;
        return new RationalNumber(num, denom);
    }

    public RationalNumber subtract(RationalNumber other) {
        int num = numerator * other.denominator - other.numerator * denominator;
        int denom = denominator * other.denominator;
        return new RationalNumber(num, denom);
    }

    public RationalNumber multiply(RationalNumber other) {
        int num = numerator * other.numerator;
        int denom = denominator * other.denominator;
        return new RationalNumber(num, denom);
    }

    public RationalNumber divide(RationalNumber other) {
        int num = numerator * other.denominator;
        int denom = denominator * other.numerator;
        return new RationalNumber(num, denom);
    }

    public String toString() {
        return numerator + "/" + denominator;
    }
}

以上代码实现了一个简单的有理数类，其中包含了加法、减法、乘法和除法的方法。通过创建RationalNumber对象，可以进行相应的有理数运算。

以下是一个示例的使用该类的代码：

public class Main {
    public static void main(String[] args) {
        RationalNumber num1 = new RationalNumber(1, 2);
        RationalNumber num2 = new RationalNumber(3, 4);

        RationalNumber sum = num1.add(num2);
        System.out.println("Sum: " + sum);

        RationalNumber difference = num1.subtract(num2);
        System.out.println("Difference: " + difference);

        RationalNumber product = num1.multiply(num2);
        System.out.println("Product: " + product);

        RationalNumber quotient = num1.divide(num2);
        System.out.println("Quotient: " + quotient);
    }
}

输出结果为：

Sum: 5/4
Difference: -1/4
Product: 3/8
Quotient: 2/3

通过这样的方式，我们可以在Java中实现有理数的运算功能。可以根据需要在有理数类中添加更多的方法，以满足不同的运算要求。