C# 数组求和,该怎么处理

C# 数组求和
int [] Tel = new int[6];
Tel[0]=12;
Tel[1]=16;
Tel[2]=43;
Tel[3]=665;
Tel[4]=23;
Tel[5]=1;
将该数组分两组求和 将结果存入ArrayList中，
如Tel [0] +Tel [2]+ Tel [4]=12+43+23=78
  Tel [1] +Tel [3]+ Tel [5]=16+665+1=682
这里不是奇数偶数 关系 是隔2个相加 也有可能数组更长 隔得是3，4，5
用循环


[解决办法]

C# code

 private void button2_Click(object sender, EventArgs e)        {            int _index = 2;//相隔几位数            int[] Tel = new int[6];            Tel[0] = 12;            Tel[1] = 16;            Tel[2] = 43;            Tel[3] = 665;            Tel[4] = 23;            Tel[5] = 1;                        ArrayList arrlist = new ArrayList();            for (int i = 0; i < 2; i++)            {                arrlist.Add(Sum(Tel,_index,i));            }            foreach (var item in arrlist)            {                MessageBox.Show(item.ToString());            }        }        private int Sum(int[] tel,int _index,int starIndex)        {            int sum = 0;            for (int i = starIndex; i < tel.Length; i += _index)            {                sum += tel[i];            }            return sum;        }