C＃在中间重启一个while循环

Question

I have a while loop that i want to restart if a condition is false, in my case. It is because i'm checking if a ip is valid and if it is then run the whole loop normal and if not i need it to restart from the start again at that point. I can't use a break and i dont want to use a goto. What is your sugestions?

This is my code, where i want to restart my while loop.

while (calculateAgain == "y")
{
    Console.Write("Your ip here: ");
    string ip = Console.ReadLine();

    IpValidation(ip);
    if (IpValidation(ip) == false)
    {
        Console.WriteLine("Ugyldig IP og eller Subnet mask!\n");
        // goto or break
    }

After this my code runs on a lot... Tell me some solutions to this other than goto.

Answer 1

You need to use the word continue

    if (IpValidation(ip) == false)
    {
        Console.WriteLine("Ugyldig IP og eller Subnet mask!\n");
        continue;
    }

This will skip the rest and go to the top of your loop.

Answer 2

There is the continue statement. If it will be hit it will skip back to the start of the loop.

while (calculateAgain == "y")
{
    // ...
    if (IpValidation(ip) == false)
    {
        Console.WriteLine("Ugyldig IP og eller Subnet mask!\n");
        continue;
    }
    Console.WriteLine("This will not be executed when continue is called");
}

Answer 3

You can do this on two ways, (by using break or continue) break will exit the loop completely, continue will just skip the current iteration.

So by reading your question. You need to use continue here, so your example might look like this:

while (calculateAgain == "y")
{
    Console.Write("Your ip here: ");
    string ip = Console.ReadLine();

    IpValidation(ip);
    if (IpValidation(ip) == false)
    {
        Console.WriteLine("Ugyldig IP og eller Subnet mask!\n");
        continue;
    }
}

This above means, for condition if (IpValidation(ip) == false) code below will be skiped (will never be executed) if condition is satisfied