帮我指点下错误 c#编程实现100以内的加法 以及 100以内偶数的加法 用方法实现

Question

using System;
class myclass
{
    public void sum(out int n)
    {   int sum=0;
    for (int i = 1; i < n; i++)

        sum += i;
   
    }
    public void sushu( out int n)
    {
        int sum1=0;
        for (int i = 1; i < n; i++)
        {    if( i% 2 == 0)
              sum1 += i;
        }
    }
}
class test
{
    static void Main()
    { myclass m=new myclass();
    int sum, sushu;
        int n=100;
        m.sum( out  n );//如何用ref
        m.sushu( out  n );
       Console.Write("sum={0},sushu={1}",sum,sushu);
       Console.Read();
   
    }
}

Answer 1

sum函数错误; for (int i = 1; i < n+1; i++)