using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace 打印正三角 {     class Program     {         static void Main(string[] args)         {             Console.WriteLine("请输入要打印的行数：");             int n=Convert.ToInt32(Console.ReadLine());             Console.Clear(); //清除以上显示的内容             //这层循环控制打印的行数             for (int i = 1; i <= n; i++)              {                 //这层循环控制每行前面打印的空格数                 for (int k = 1; k <= n - i; k++)                  {                     Console.Write(" ");                 }                 //这层循环控制每行前面打印*的个数                 for (int j = 1; j <= 2 * i - 1; j++)                 {                     Console.Write("*");                 }                 //每打印完一行换一下行                 Console.Write("\n");             }             Console.ReadKey();         }     } }