输入一个数字，在控制台输出其对应的月份和该月份对应的天数。
package ch2;
import java.util.*;
public class SwitchOP {
public static void main(String[] args) {
System.out.println("请输入月份：");
Scanner scanner=new Scanner(System.in);
int month=scanner.nextInt();
switch(month){
case 1: System.out.println("一月有31天");break;
case 2: System.out.println("二月有28/29天");break;
case 3: System.out.println("三月有31天");break;
case 4: System.out.println("四月有30天");break;
case 5: System.out.println("五月有31天");break;
case 6: System.out.println("六月有30天");break;
case 7: System.out.println("七月有31天");break;
case 8: System.out.println("八月有31天");break;
case 9: System.out.println("九月有30天");break;
case 10: System.out.println("十月有31天");break;
case 11: System.out.println("十一月有30天");break;
case 12: System.out.println("十二月有31天");break;
default: System.out.println("无效月份.");
}
}
}