java switch用法

满足那个条件，就从那个入口进入，没有break就继续（是这样设计的，需要自己加break;），一般都是要加break的。 switch (表达式)  表达式只能是【整型、char、String.】

import java.util.Scanner;

public class testSwitch {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("请输入一个数字（1-4）：");
        int number = scanner.nextInt();

        System.out.print("数字是："+number+'\n');
        String season;
        switch (number) {
            case 1:
                season = "春季";
                break;
            case 2:
                season = "夏季";
                break;
            case 3:
                season = "秋季";
                break;
            case 4:
                season = "冬季";
                break;
            default:
                season = "输入错误";
                break;
        }

        System.out.println("对应的季节是：" + season);

        scanner.close();
    }
}

判断成绩

package IfWhileFor;
import java.util.Scanner;

public class TestSwitch02 {

    public static void main(String[] args) {

                char grade = 'A'; // 假设学生成绩为B

                switch (grade) {
                    case 'A':
                        System.out.println("优秀");
                        break;
                    case 'B':
                        System.out.println("良好");
                        break;

                    case 'C':

                        System.out.println("中等");
                        break;
                    case 'D':
                        System.out.println("差");
                        break;

                    default:
                        System.out.println("未知");

                }
            }

}

判断方向

package IfWhileFor;

public class TestSwitch03 {

    public static void main(String[] args) {

                char grade = 'A'; //

                switch (grade) {
                    case 'A':
                        System.out.println("****向左***");
                        break;
                    case 'D':
                        System.out.println("****向右***");
                        break;

                    case 'W':

                        System.out.println("****向上***");
                        break;
                    case 'S':
                        System.out.println("****向下***");
                        break;

                    default:
                        System.out.println("****不动***");

                }
            }

}