求1+2+3+4+……+100之和 递归算法

using  System;
using  System.Collections.Generic;
using  System.Text;

namespace  RecursionSum
... {
    class RecursionSum
    ...{
        public static void Main(string[] args)
        ...{
            int n = Convert.ToInt32(Console.ReadLine());
            RecursionSum r = new RecursionSum();
            Console.WriteLine(r.iRecursionSum(n));
            Console.ReadLine();
            return;
        }
        public int iRecursionSum(int i)
        ...{
            if (i > 0)
                return i + iRecursionSum(i - 1);
            else
                return i;
        }
    }
}