do
{
Console.WriteLine("请输入数字"); strNumber = Console.ReadLine();
if (strNumber != "q")
{ int number = Convert.ToInt32(strNumber);
Console.WriteLine("这个数字的2倍是{0}", number * 2);
Console.WriteLine("输入有误，请重新输入");
}
else {
Console.WriteLine("你输入的是q，程序退出！！！");
}
} while (strNumber != "q"); Console.ReadKey();
图片发自简书App
