¢编写一个计算器，完成+-*/ 运算 ¢ （1）定义一个接口Compute含有一个方法 int computer(int a,int b); （2）设计四个类分别实现此接口，完成+-*/运算 （3）设计一个测试类，完成+-*/运算，输出如下运行结果：

以下是 Java 代码实现：

// 计算器接口
interface Compute {
    int compute(int a, int b);
}

// 加法类
class Add implements Compute {
    public int compute(int a, int b) {
        return a + b;
    }
}

// 减法类
class Subtract implements Compute {
    public int compute(int a, int b) {
        return a - b;
    }
}

// 乘法类
class Multiply implements Compute {
    public int compute(int a, int b) {
        return a * b;
    }
}

// 除法类
class Divide implements Compute {
    public int compute(int a, int b) {
        if (b == 0) {
            throw new IllegalArgumentException("除数不能为 0！");
        }
        return a / b;
    }
}

// 测试类
public class Calculator {
    public static void main(String[] args) {
        Compute add = new Add();
        Compute subtract = new Subtract();
        Compute multiply = new Multiply();
        Compute divide = new Divide();

        int a = 10, b = 5;

        System.out.println(a + " + " + b + " = " + add.compute(a, b));
        System.out.println(a + " - " + b + " = " + subtract.compute(a, b));
        System.out.println(a + " * " + b + " = " + multiply.compute(a, b));
        System.out.println(a + " / " + b + " = " + divide.compute(a, b));
    }
}

输出结果：

10 + 5 = 15
10 - 5 = 5
10 * 5 = 50
10 / 5 = 2