2018-12-20等腰三角形

Console.Write("请输入等腰三角形的行数：");
        int a = Convert.ToInt32(Console .ReadLine ());
        for (int b = 0; b < a; b++)
        {
            for (int c = 0; c < a - b - 1; c++)
            {
                Console.Write(" ");
            }
            for (int d = 0; d < 2 * b + 1; d++)
            {
                Console.Write  ("*");
            }
            Console.WriteLine("\n");
        }
        Console .ReadKey ();