using System;


namespace C____作业练习
{
    class Program
    {
        static void Main(string[] args)
        {
           int[,]a= new int[4,4] { { 1,2,3,4},{ 5,6 , 7, 8 }, { 9, 10, 11, 12 } ,{ 13, 14,15,16 } };
            //构造4*4数组

            int sum = 0;

            for (int i = 0; i < 4; i++) {
                sum += a[i,i]+a[i,3-i];
                    }
          
            Console.Write("对角线元素之和为："+sum+"\n");
            
        }
    }
}