switch简易计算器

package demo01;
import java.util.Scanner;
public class demo01 {
	public static void main(String[] args) {
		System.out.println("请选择2数运算:(1~4之间的数字)");
		System.out.println("\t\t1.加法 ");
		System.out.println("\t\t2.减法");
		System.out.println("\t\t3.乘法 ");
		System.out.println("\t\t4.除法 ");
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		switch (a) {
		case 1:
			System.out.println("请输入数一：");
			int num1 = sc.nextInt();
			System.out.println("请输入数二：");
			int num2 = sc.nextInt();
			System.out.println(num1 + "+" + num2 + "=" + (num1 + num2));
			break;
		case 2:
			System.out.println("请输入数一：");
			double num3 = sc.nextInt();
			System.out.println("请输入数二：");
			double num4 = sc.nextInt();
			System.out.println(num3 + "-" + num4 + "=" + (num3 - num4));
			break;
		case 3:
			System.out.println("请输入数一：");
			double num5 = sc.nextInt();
			System.out.println("请输入数二：");
			double num6 = sc.nextInt();
			System.out.println(num5 + "*" + num6 + "=" + (num5 * num6));
			break;
		case 4:
			System.out.println("请输入数一：");
			double num7 = sc.nextInt();
			System.out.println("请输入数二：");
			double num8 = sc.nextInt();
			System.out.println(num7 + "/" + num8 + "=" + (num7 / num8));
			break;
		default:
			System.out.println("菜单选择输入有误.");
		}
		System.out.println("欢迎使用本计算器.");
	}
}