C#：简单递归累加算法

 1 namespace demo
 2 {
 3     public class Program
 4     {
 5         static void Main(string[] args)
 6         {
 7             int res = Sum(100);
 8         }        
 9         static int Sum(int n)
10         {
11             if (n <= 1)
12                 return n;
13             return n+Sum(n - 1);
14         }
15     }
16 }