求任意年份任意月份的天數

import java.util.Scanner;
/**
 * 求任意一年任意一月的天數
 * @author KiMin
 *  2012-11-29
 */
public class Test {
 
 public static void main(String[] args) {
  
  Scanner scan = new Scanner(System.in);
  
  System.out.print("請出入年份：");
  int year = scan.nextInt();
  System.out.println("請出入月份：");
  int month = scan.nextInt();
  
  int datOfMonth = 0;
  
  switch (month) {
  case 1:
  case 3:
  case 5:
  case 7:
  case 8:
  case 10:
  case 12:
   datOfMonth = 31;
   break;
  case 2:
   if (isRunNian(year)) {
    datOfMonth = 29;
   } else {
    datOfMonth = 28;
   }
   break;
  default:
   datOfMonth = 30;
   break;
  }
  
  System.out.println(year + "年的" + month + "月共有" + datOfMonth + "天");
 }
 
 // 判斷是否是閏年
 public static boolean isRunNian (int year) {
  boolean flag = false;
  
  if (year/4 == 0 
    || (year/100 == 0 && year/400 != 0)) {
   flag = true;
  }
  
  return flag;
 }
}