Java 浅做计算器

package www.nihao;
import java.util.Scanner;
public class counter {
    public static void main(String[] args) {
Scanner scanner=new Scanner(System.in);

    System.out.println("请输入两个操作数：");
    int number1 = scanner.nextInt();
    int number2 = scanner.nextInt();
    System.out.println("请选择你要计算的法则：");
    System.out.println("1.加法");
    System.out.println("2.减法");
    System.out.println("3.乘法");
    System.out.println("4.除法");
    int rule = scanner.nextInt();
    switch (rule) {
        case 1:
            System.out.println(add(number1, number2));
            break;
        case 2:
            System.out.println(minus(number1, number2));
            break;
        case 3:
            System.out.println(multiply(number1, number2));
            break;
        case 4:
            System.out.println(division(number1, number2));
            break;
        default:
            return;}

    scanner.close();
}

    public static int add(int a,int b){
        int sum;
        sum=a+b;
        return sum;
    }
    public static int minus(int a,int b){
        int sum;
        sum=a-b;
        return sum;
    }
    public static int multiply(int a,int b){
        int sum;
        sum=a*b;
        return sum;
    }
    public static int division(int a,int b){
        int sum;
        sum=a/b;
        return sum;
    }

}