How to break nested foreach loop then go to parent foreach loop on c#

Question

I have the following code:

foreach(// Some condition here)
{
    while (// Some condition here)
    {
        foreach (// Some condition here)
        {
             if (// Condition again)
             {
                  //Do some code
             }
             if (// Condition again)
             {
                 //Stop the first foreach then go back to first foreach
             }
        }
    }
}

What I want to do is when I hit the 2nd if statement on the last foreach loop is to return on the first foreach loop.

Note: If the 2nd if statement is not true, it should continue the last foreach loop until the condition is not true.

Thanks in advance!

@rapsalands break will only exit the current loop, in this case the innermost foreach. OP wants to exit both inner loops, that is the innermost foreach and while. — Nolonar
– Nolonar, Commented Jul 11, 2013 at 10:26

Henk Holterman · Accepted Answer · 2013-07-11 10:20:19Z

38

The only way to this directly is with a goto.

Another (better) option is to restructure until the problem goes away. For instance by putting the inner code (while + foreach) in a method and use return to get back.

answered Jul 11, 2013 at 10:20

Henk Holterman

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9 Comments

Sayse Over a year ago

Just as a note, my old university lecturer categorically stated he would fail anyone using goto :)

Gerald Over a year ago

I think I should do the second option where I should put the while and foreach on a new method. Thanks for the suggestion!

Chuu Over a year ago

@Sayse Then that lecturer was an idiot. As a simple example, the idiomatic way to do cleanup in C uses gotos. Without fail new programmers on various C mailing list try to argue against it because of bias against goto and then someone has to explain why the idiom exists.

Rob van der Veer Over a year ago

I don't like goto's. When teaching students, it is a good approach to avoid using them. The point is to have them learn to use proper looping constructs and to think about program flow. After some years of practice, developers learn a style and know when the use of a goto is appropriate. Calling a teacher names isn't helpful either.

Rob van der Veer Over a year ago

Thinking about it, we had a C language teacher in the early days that failed anyone using the return statement mid-function), which made even uglier code, but definitely taught us about logic. I think i can safely say he died of a heart attack when C# came with the yield statement.

|

Dusan · Accepted Answer · 2013-07-11 10:24:38Z

17

Something like this:

resetLoop = false;
for(// Some condition here)
{
    while (// Some condition here)
    {
        foreach (// Some condition here)
        {
             if (// Condition again)
             {
                  //Do some code
             }
             if (// Condition again)
             {
                 //Stop the first foreach then go back to first foreach
                 resetLoop = true;
                 break;
             }
        }
        if (resetLoop) break;
    }
    if (resetLoop) {
        // Reset for loop to beginning
        // For example i = 0;
    }
}

answered Jul 11, 2013 at 10:24

Dusan

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1 Comment

David Colwell Over a year ago

I posted the same code, first in best served tho, credit to you. but for the love of all that is holy, preface your code with //Here be dragons so that newbie coders do not think this is the right way to code

Sayse · Accepted Answer · 2013-07-11 10:27:29Z

12

Noone has mentioned it (Henk mentioned briefly) yet but the best approach would be to move your loops into its own method and use return

public ReturnType Loop(args)
{
foreach outerloop
    foreach innerLoop
       if(Condition)
          return;
}

answered Jul 11, 2013 at 10:27

Sayse

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Comments

annemartijn · Accepted Answer · 2015-11-13 08:36:57Z

6

As i see you accepted the answer in which the person refers you goto statement, where in modern programming and in expert opinion goto is a killer, we called it a killer in programming which have some certain reasons, which i will not discuss it over here at this point, but the solution of your question is very simple, you can use a Boolean flag in this kind of scenario like i will demonstrate it in my example:

foreach(// Some condition here)
{
    //solution
    bool breakme = false;

    while (// Some condition here)
    {
        foreach (// Some condition here)
        {
            if (// Condition again)
            {
                //Do some code
            }
            if (// Condition again)
            {
                //Stop the first foreach then go back to first foreach
                breakme = true;
                break;
            }
        }
    }
    if(breakme)
    {
        break;
    }
}

simple and plain. :)

edited Nov 13, 2015 at 8:36

annemartijn

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answered Mar 19, 2015 at 11:12

HTU

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2 Comments

Gerald Over a year ago

Thanks for the answer. However, if you read my comment on that answer, I followed his second suggestion wherein just put it on a new method.

HTU Over a year ago

:) my pleasure... i didn't read your comment, and that is ok, i told you my suggestion, now up to you... :)

Eyal H · Accepted Answer · 2013-07-11 10:26:45Z

As said before me, I also recommend to re-factor the code and see if it is absolutely necessary to have 3 loops nested one in another. If it is, and I assume there is some logic involve, you should consider splitting into sub functions (as suggested)

For a simple code solution:

foreach(// Some condition here)
{
    var broke = false;
    while (// Some condition here)
    {
        foreach (// Some condition here)
        {
             if (// Condition again)
             {
                  //Do some code
             }
             if (// Condition again)
             {
                 //Stop the first foreach then go back to first foreach
                 broke = true;
                 break;
             }
        }
        if (broke) break;
        // continue your while loop
    }
}

Jaapjan · Accepted Answer · 2013-07-11 10:21:43Z

3

var broken = false;
foreach(// Some condition here)
{
    broken = false;
    while (!broken && // Some condition here)
    {
        foreach (// Some condition here)
        {
             if (// Condition again)
             {
                 //Do some code
             }
             if (// Condition again)
             {
                 //Stop the first foreach then go back to first foreach
                 broken = true;
                 break;
             }
        }
    }
}

answered Jul 11, 2013 at 10:21

Jaapjan

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