Código de C sharp - Pirámide inversa con letras

using System;

class GFG {

    // function for inverse pyramid print

    static void pyramid(int n)

    {

        int i, j, num, gap;

        // outer loop to handle number

        // of rows n in this case

        for (i = n; i >= 1; i--) {

            // inner loop to create right triangle

            // gaps on left side of pyramid

            for (gap = n - 1; gap >= i; gap--) {

                Console.Write(" ");

                Console.Write(" ");

            }

            // initializing value corresponding

            // to ASCII value of 'A'

            num = 'A';

            // loop to print characters on

            // left side of pyramid

            for (j = 1; j <= i; j++) {

                Console.Write((char)num++ + " ");

            }

            // loop to print characters on

            // right side of pyramid

            for (j = i - 1; j >= 0; j--) {

                Console.Write((char)--num + " ");

            }

            Console.WriteLine("");

        }

    }

    /* Driver program to test above function */

    public static void Main()

    {

        int n = 9;

        pyramid(n);

    }

}