java接口实现简单计算器

import java.text.DecimalFormat;
import java.util.Scanner;

public class Test006 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("输入m：");
        int m = sc.nextInt();
        System.out.println("输入n：");
        int n = sc.nextInt();

        Fun fun = new Fun();
        System.out.print("加法：");fun.func(new Addition(),m,n);
        System.out.print("减法：");fun.func(new Subtraction(),m,n);
        System.out.print("乘法：");fun.func(new Multiplication(),m,n);
        System.out.print("除法：");fun.func(new Division(),m,n);
    }

}


interface Calculator{
    Object compute(int a, int b);
}

/*
加法
 */
class Addition implements Calculator{

    @Override
    public Object compute(int a, int b) {
        return a + b;
    }
}

/*
减法
 */
class Subtraction implements Calculator{

    @Override
    public Object compute(int a, int b) {
        return a - b;
    }
}


/*
乘法
 */
class Multiplication implements  Calculator{

    @Override
    public Object compute(int a, int b) {
        return a * b;
    }
}


/*
除法
 */
class  Division implements  Calculator{

    @Override
    public Object compute(int a, int b) {

        if (b != 0) {
            DecimalFormat df = new DecimalFormat("0.0000");

           // System.out.println(df.format((float) a / b));
            return (df.format((float) a / b));
        }
        System.out.println("错误信息：分母不能为0");
        return 0;


    }
}

class Fun{
    public void func(Calculator calculator,int a,int b){
        System.out.println(calculator.compute(a, b));
    }
}