C#递归题目代码

 1 public class MainClass 2  3 { 4  5 public static void Main() 6  7 { 8  9 Console.WriteLine(Foo(30));10 11 }12 13 public static int Foo(int i)14 15 {16 17 if (i <= 0)18 19 return 0;20 21 else if(i > 0 && i <= 2)22 23 return 1;24 25 else return Foo(i -1) + Foo(i - 2);26 27 }28 29 }