C#_杨辉三角形

var a = new int[5, 5];
            for (int i = 0; i < a.GetLength(0); i++)
            {
                a[i,0] = 1;
            }
            for (int i = 1; i <a.GetLength(0); i++)
            {
                for (int j = 1; j < a.GetLength(1); j++)
                {
                    a[i, j] = a[i - 1, j - 1] + a[i - 1, j];
                }
            }
            for (int i = 0; i < a.GetLength(0); i++)
            {
                for (int k = 1; k <=4-i; k++)
                {
                    Console.Write("\t");
                }
                for (int j = 0; j <=i; j++)
                {
                    Console.Write(a[i, j]+"\t\t");
                }
                Console.WriteLine();
            }
            Console.ReadKey();