Java基础--switch case语句入门小练习

练习一练习二练习三补充

package switchDemo;
import java.util.Scanner;
public class Test1 {
    public static void main(String[] args) {
        

        
        //当month值与case后面的值匹配之后，就认为从匹配的地方开始后面代码都可以执行。
        //我们在输出语句之后加上break就可以啦。
        Scanner input=new Scanner(System.in);
        System.out.println("请输入相应的月份");
        int month=input.nextInt();
        switch(month){
            case 1:
                System.out.println("冬季");
                break;
            case 2:
                System.out.println("冬季");
                break;
            case 3:
                System.out.println("春季");
                break;
            case 4:
                System.out.println("春季");
                break;
            case 5:
                System.out.println("春季");
                break;
            case 6:
                System.out.println("夏季");
                break;
            case 7:
                System.out.println("夏季");
                break;
            case 8:
                System.out.println("夏季");
                break;
            case 9:
                System.out.println("秋季");
                break;
            case 10:
                System.out.println("秋季");
                break;
            case 11:
                System.out.println("秋季");
                break;
            case 12:
                System.out.println("冬季");
                break;
            default:
                System.out.println("月份有误");
        }
        input.close();
    }
}

简洁写法：

package switchDemo;

import java.util.Scanner;

public class Test2 {
    public static void main(String[] args) {
        
        Scanner input=new Scanner(System.in);
        System.out.println("请输入相应的月份");
        int month=input.nextInt();
        switch(month){
            case 1:
            case 2:
            case 12:
                System.out.println("冬季");
                break;
            case 3:
            case 4:
            case 5:
                System.out.println("春季");
                break;
            case 6:
            case 7:
            case 8:
                System.out.println("夏季");
                break;
            case 9:
            case 10:
            case 11:
                System.out.println("秋季");
                break;
            default:
                System.out.println("月份有误");
        }
        input.close();
    }
}

package switchDemo;
import java.util.Scanner;
public class Test3 {
    public static void main(String[] args) {
        
        Scanner input=new Scanner(System.in);
        System.out.println("请输入年份");
        int year=input.nextInt();
        System.out.println("请输入月份");
        int month=input.nextInt();
        switch(month){
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12:
                System.out.println(year+"年"+month+"月有31天");//+做文字拼接
                break;
            case 6:
            case 9:
            case 11:
                System.out.println(year+"年"+month+"月有30天");
                break;
            case 2:
                if(year%4==0){
                    System.out.println(year+"年"+month+"月有29天");
                }else{
                    System.out.println(year+"年"+month+"月有28天");
                }
                break;
            default:
                System.out.println("月份有误");
        }
        input.close();
    }
}

package switchDemo;
import java.util.Scanner;
public class Test5 {
    public static void main(String[] args) {
        
        Scanner sc =new Scanner(System.in);
        System.out.println("请录入分数");
        int score =sc.nextInt();
        int grade =score/10;//
        
        switch (grade){
            case 0:
            case 1:
            case 2:
            case 3:
            case 4:
            case 5:
                System.out.println("不及格");
                break;
            case 6:
                System.out.println("及格");
                break;
            case 7:
                System.out.println("一般");
                break;
            case 8:
                System.out.println("良好");
                break;
            case 9:
            case 10:
                System.out.println("优秀");
                break;
            default:
                System.out.println("分数有误");
        }
        sc.close();
    }
}

package switchDemo;

public class Test4 {
    public static void main(String[] args) {
        // byte short int (long不行)
        short a=10;
        switch(a){
            case 10:
                System.out.println("可以运行");
        }

        // char
        char b='a';
        switch(b){
            case 'a' :
                System.out.println("可以运行");
        }

        // boolean不行

        // String
        String c="hello";
        switch(c){
            case "hello":
                System.out.println("可以运行");
        }

        // enum(枚举)--也可以运行，后面再讲
    }
}