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I break the code of the for loop without using break like I have for loop given below.And when i is 1 or 2 or 3 or any else but if condition is true then loop will be terminated because i will be 5 if the condition is true.And so NO need of break is needed there.Beacause I do not want to use break.I have done like this here.It works.

int myCondition=0;
bool flag=false;
for(int i=0;i<5;i++)
{
   if(myCondition==0)
   {
       flag=true;
   }
   if(flag)
       i=5;
}

But now I want to use foreach loop and in this loop when some condition is true then I want to break the foreach loop code.So what should I do here for breaking the foreach loop code without using break ? Like in the above for loop I have initialize i to 5 when condition is true.In the foreach loop anything like that to do to avoid break.

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7
  • 7
    Why not use break? That's what it's there for... Commented Mar 17, 2010 at 11:52
  • @Nick Craver.. Is it ok to use break in our code ? Commented Mar 17, 2010 at 11:54
  • 1
    @Harikrishna - Absolutely, it's a fundamental feature of the language. I think goto is what you're thinking of, and traditionally yes you should steer clear of that (for readability mainly) Commented Mar 17, 2010 at 11:56
  • 2
    Of course it's OK. It's wrong NOT to use it. Unless you can give me a good reason why not? Commented Mar 17, 2010 at 11:56
  • 1
    @Harikrisha: For an answer to your last comment, see this stackoverflow.com/questions/46586/goto-still-considered-harmful Commented Mar 17, 2010 at 12:07

7 Answers 7

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10

You should use what's in the language. There's no need to avoid break - just use it. Or to put it another way, "I don't want to use break" is not a good enough justification: if you think you've got a really good reason not to use it, then you should explain that reason. Don't hobble yourself by pretending perfectly reasonable features don't exist, and coming up with convoluted schemes to avoid them.

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6 Comments

Would you apply this same reasoning to goto? Or would you turn it around for goto and say that you better have a good reason to use before it's acceptable?
@tvanfosson: If you're in a situation where goto provides the cleanest way to express yourself (which is very occasionally the case in a switch statement) then yes, I'd use the same reasoning. It's considerably rarer than break though.
goto is also a keyword that is there for a reason. If you have the perfect candidate for 'goto' in your code, why not use it?
@Axarydax - I don't think anyone disagrees there, just that the "perfect candidate" is very, very rare.
@Jon - I'd say there's a presumption of guilt for a goto rather than a presumption of innocence. I can't really think of any situations where I'd prefer it over another mechanism except as a glorified break -- transferring control from the innermost loop of several nested loops to the statement following the looping constructs. Even the switch case I'd prefer to refactor to call a method rather than transfer to a block via goto.
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Don't do it.

Your manipulation of 'i' in the for loop is questionable already. Trying to mess with the iterator in a foreach-loop would be downright dirty. If it compiles at all.

I would write your example with a break or as:

bool myCondition=false;
for(int i=0;i<5 && !myCondition;i++)
{
   ....
}

In a foreach loop, when you're done before the entire sequence is complete, just call break

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4 Comments

@Harikrishna: The difference between break and goto is that usually there are cleaner ways of expressing the same control flow than using goto; break is a natural way of expressing a reasonably common control flow.
Reluctantly, because of the limitations of break, we use goto to get out of nested loops.
That's where the labeled break in Java is occasionally useful. Mind you, I find that refactoring the loops into separate methods often leads to cleaner code at that point anyway.
@Jon, agreed. A concrete example could probably be solved even better with LINQ. But it is a 'problem' with many gradations.
4

This is probably going to get me downvoted... but you should use the break keyword.

Failing that:

foreach(var foo in bar)
{
  if(condition)
  {
    //perform normal loop code
    //set condition if required.
  }
  //otherwise do nothing - the loop will iterate all the way to the end without 
  //doing anything.
}

You could be more expressive and use if(condition){ /*blah*/}else { continue; } inside the loop - but either way it does the same thing.

You can't do much else to break out of a for each other than:

  • Use break
  • Throw an Exception
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Comments

2

In general, the 'pattern' you describe here is a code smell. It is NOT a good idea to change the index variable in a for-loop. It can result in unreadable, hard-to-maintain code, especially if the loop grows large.

That being said, why would you not want to use the break keyword. It is meant for this purpose, and whatever downside it has (in your opinion) is still a far better solution than the one you describe here.

Last, I see no way to do the same thing using a foreach loop in a sensible way.

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1

Not using break in your for(;;) loop is a serious stylistic mistake. But you'll get away with it. But not when you use foreach, you have to use the break keyword.

Pay attention to the title of this blog post.

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1

Well, thats why there is this comand "break". I have no reasons why shouldnt you use it.

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0

Your code should absolutely be:

bool myCondition = false;

for(int i=0;i<5;i++)
{
   // do stuff
   if(myCondition)
      break;
}

Not only are you using the commands (i.e. tools) provided by the language, but you are keeping the code very readable, and maintainable. The break command is fundamental to the language.

Trying to come up with some reason not to use break is like doing math on a calculator -- literally, turn the calculator over, get a silver paint marker, and do some math. You are crippling yourself by not using the tools in front of you.

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