代码如下：
/*
输入一个年和月，输出该月对应的天数
*/
import java.util.Scanner;
class Demo10
{
public static void main(String[] args)
{
Scanner sc=new Scanner(System.in);
System.out.println("请输入年和月");
int year=sc.nextInt();
int month=sc.nextInt();
//判断月的天数
int days=0;
switch(month){
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12: days=31; break;
case 2:
if(year%4==0&&year%100!=0||year%400==0)
days=29;
else
days=28;
break;
case 4:
case 6:
case 9:
case 11: days=30;break;
default: System.out.println("你输入的代表月份的数字不合理，请重新输入");
}
System.out.println(year+"年"+month+"月有："+days+"天");
}
}