How to go to the next value of a While loop

Question

I have a While loop that reads a line of a file.txt. I also have a method named VerifyPhoto that returns true/false I want to go to next item of the while loop if the returned value is false. How Could I do that ? I tried break and return but it just leave all and back to the form...

while (!reader.EndOfStream)
  {
     if(VerifyPhoto(filed.matriculation) == false)
        {
          //go to the next line of the file.txt
        }
  }

`break` to leave the current loop, `return` to leave the method entirely, `continue` to skip the current iteration and go to the next. I guess you're looking for `continue` — Nolonar, Feb 04 '13 at 12:55
Just thought I'd mention it now, since `break`, `return` and `continue` are all related to this: `goto`. All of these keywords are so-called **jumps**. However, `goto` is old and considered bad practice, because code using `goto` are very difficult to follow. The 3 former keywords are basically all `goto`, but they are at least a lot easier to follow. Btw. I still remember the time I had to work with a language that did not implement any of those, so I had to juggle with `bool`s. It was horror to implement, and horror to debug... — Nolonar, Feb 04 '13 at 13:02
I remeber `goto` when I was working with `C` haha! My professor called it `Spaghetti programming` '-' . Really thanks, I didn't know the difference between the `jumps` — Ghaleon, Feb 04 '13 at 13:05

Patryk Ćwiek · Accepted Answer · 2013-02-04T12:59:16.287

10

You may want to get familiar with other control statement: continue

[EDIT] Newest version of the doc: continue, thanks Jeppe.

edited Feb 04 '13 at 12:59

answered Feb 04 '13 at 12:49

Patryk Ćwiek

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It will ignore all the rest inside the while and go to the next iteration ? – Ghaleon Feb 04 '13 at 12:51
@Ghaleon Yes, it will, just like in the example given. :) When you use `continue`, it will literally continue to the next iteration, just like `break` breaks out of the loop. – Patryk Ćwiek Feb 04 '13 at 12:53
[Newest version of MSDN `continue` doc](http://msdn.microsoft.com/en-us/library/923ahwt1.aspx). – Jeppe Stig Nielsen Feb 04 '13 at 12:57

score 1 · Answer 2 · answered Feb 04 '13 at 12:49

1

continue; (some more to make it 30 chars)

answered Feb 04 '13 at 12:49

paul

21,653
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score 0 · Answer 3 · answered Feb 04 '13 at 12:53

0

Depending on your actual code, maybe you could simply invert the boolean test, so you do something only if VerifyPhoto returns true:

while (...)
{
    if(VerifyPhoto(filed.matriculation))
    {
        // Do the job
    }
}

answered Feb 04 '13 at 12:53

ken2k

48,145
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But one thing i'll verify is if there's an item on a `CheckedListBox` having it or not i'll do the job, but I have these other test ;s Thanks ! – Ghaleon Feb 04 '13 at 12:55

score 0 · Answer 4 · answered Feb 04 '13 at 12:54

The continue statement passes control to the next iteration of the enclosing iteration statement in which it appears

while (!reader.EndOfStream)
{
    if(VerifyPhoto(filed.matriculation) == false)
    {
        continue;
        //go to the next line of the file.txt
    }
}

score 0 · Answer 5 · answered Feb 04 '13 at 12:56

Am I missing something in the way you are doing this? Do you read the first line before starting the loop? if so don't you need something like

**string line;**
while (!reader.EndOfStream)
  {
     if(VerifyPhoto(filed.matriculation) == false)
        {
          //go to the next line of the file.txt
          **line = file.ReadLine();**
        }
  }

score 0 · Answer 6 · answered Feb 04 '13 at 12:56

If you're trying to read line by line then File.ReadLines may be useful.

Also what you're looking for is the continue statement.

string myFile = @"c:\path\to\my\file.txt";

foreach(string line in File.ReadLines(myFile))
{
    //Do stuff
    //if(!VerifyPhoto())
    //    continue;
    //Do other logic
}

How to go to the next value of a While loop

6 Answers6

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