奶牛问题

 1 public class Test {
 2     private static int sum=1;
 3     private static void giveBirth(int year)
 4     {
 5         if(year>3)
 6             sum+=year-3;
 7         for(year=year-3;year>0;year--)
 8         {
 9             giveBirth(year);
10         }
11     }
12     public static void main(String[] args)
13     {
14         System.out.println("please input years:");
15         Scanner scanner=new Scanner(System.in);
16         int year=Integer.parseInt(scanner.nextLine());
17         giveBirth(year);
18         System.out.println(sum);
19     }
20 }