C# 如果 else 为真，我怎样才能让程序循环回到开始？C＃
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How can I make a program loop back to the start if else is true? C#
提问by WhereAreYouSyntax
Couldn't find any other answer on the site that covers this. If else is run and an error message is displayed, is it possible to restart the program by looping back to the start instead of restarting the console?
在网站上找不到涵盖此内容的任何其他答案。如果 else 运行并显示错误消息，是否可以通过循环回到开始而不是重新启动控制台来重新启动程序？
class Program
{
static void Main(string[] args)
{
int User;
int Array;
StreamWriter outfile = new StreamWriter("C://log.txt");
Console.WriteLine("Input an number between 1 and 100");
User = Convert.ToInt32(Console.ReadLine());
if (User < 101 && User > 0)
{
for (Array = 1; Array <= User; Array++)
{
Console.WriteLine(Array + ", " + Array * 10 * Array);
outfile.WriteLine(Array + ", " + Array * 10 * Array);
}
{
Console.WriteLine("Press Enter To Exit The Console");
outfile.Close();
Console.ReadLine();
}
}
else
{
Console.WriteLine("Sorry you input an invalid number. ");
Console.ReadLine();
}
}
}
Sorry! To be more clear I need to make the Program start again if the user inputs an invalid number
对不起！为了更清楚，如果用户输入无效数字，我需要重新启动程序
Thanks for the help!
谢谢您的帮助！
采纳答案by System Down
An easy way of doing this is placing your code inside a while loop, so that the code keeps repeating. The only way to exitthe loop would be for the condition you just set in the ifclause to be true. So something along the lines of:
一个简单的方法是将您的代码放在一个 while 循环中，以便代码不断重复。退出循环的唯一方法是您刚刚在if子句中设置的条件为真。所以类似的东西：
class Program
{
static void Main(string[] args)
{
int User;
int Array;
bool isUserWrong = true; //This is a flag that we will use to control the flow of the loop
StreamWriter outfile = new StreamWriter("C://log.txt");
while(isUserWrong)
{
Console.WriteLine("Input an number between 1 and 100");
User = Convert.ToInt32(Console.ReadLine());
if (User < 101 && User > 0)
{
for (Array = 1; Array <= User; Array++)
{
Console.WriteLine(Array + ", " + Array * 10 * Array);
outfile.WriteLine(Array + ", " + Array * 10 * Array);
}
isUserWrong = false; // We signal that we may now leave the loop
}
else
{
Console.WriteLine("Sorry you input an invalid number. ");
Console.ReadLine();
//Note that here we keep the value of the flag 'true' so the loop continues
}
}
Console.WriteLine("Press Enter To Exit The Console");
outfile.Close();
Console.ReadLine();
}
}
回答by Logan Murphy
You can do this instead
你可以这样做
User = Convert.ToInt32(Console.ReadLine());
while (User >= 101 || User <= 0)
{
Console.WriteLine("Sorry you input an invalid number. ");
User = Convert.ToInt32(Console.ReadLine());
}
回答by crownedzero
This would be a good use for the do-while loop in Java:
这对 Java 中的 do-while 循环很有用：
class DoWhileDemo {
public static void main(String[] args){
int count = 1;
do {
System.out.println("Count is: " + count);
count++;
} while (count < 11);
}
}
