C# loop - break vs. continue

Question

In a C# (feel free to answer for other languages) loop, what's the difference between break and continue as a means to leave the structure of the loop, and go to the next iteration?

Example:

foreach (DataRow row in myTable.Rows)
{
    if (someConditionEvalsToTrue)
    {
        break; //what's the difference between this and continue ?
        //continue;
    }
}

Answer 1

break will exit the loop completely, continue will just skip the current iteration.

For example:

for (int i = 0; i < 10; i++) {
    if (i == 0) {
        break;
    }

    DoSomeThingWith(i);
}

The break will cause the loop to exit on the first iteration - DoSomeThingWith will never be executed. This here:

for (int i = 0; i < 10; i++) {
    if(i == 0) {
        continue;
    }

    DoSomeThingWith(i);
}

Will not execute DoSomeThingWith for i = 0, but the loop will continue and DoSomeThingWith will be executed for i = 1 to i = 9.

Answer 2

To break completely out of a foreach loop, break is used;

To go to the next iteration in the loop, continue is used;

Break is useful if you’re looping through a collection of Objects (like Rows in a Datatable) and you are searching for a particular match, when you find that match, there’s no need to continue through the remaining rows, so you want to break out.

Continue is useful when you have accomplished what you need to in side a loop iteration. You’ll normally have continue after an if.

Answer 3

A really easy way to understand this is to place the word "loop" after each of the keywords. The terms now make sense if they are just read like everyday phrases.

break loop - looping is broken and stops.

continue loop - loop continues to execute with the next iteration.

Answer 4

Simple answer:

Break exits the loop immediately.
Continue starts processing the next item. (If there are any, by jumping to the evaluating line of the for/while)

Answer 5

There are more than a few people who don't like break and continue. The latest complaint I saw about them was in JavaScript: The Good Parts by Douglas Crockford. But I find that sometimes using one of them really simplifies things, especially if your language doesn't include a do-while or do-until style of loop.

I tend to use break in loops that are searching a list for something. Once found, there's no point in continuing, so you might as well quit.

I use continue when doing something with most elements of a list, but still want to skip over a few.

The break statement also comes in handy when polling for a valid response from somebody or something. Instead of:

Ask a question
While the answer is invalid:
    Ask the question

You could eliminate some duplication and use:

While True:
    Ask a question
    If the answer is valid:
        break

The do-until loop that I mentioned before is the more elegant solution for that particular problem:

Do:
    Ask a question
    Until the answer is valid

No duplication, and no break needed either.

Answer 6

if you don't want to use break you just increase value of I in such a way that it make iteration condition false and loop will not execute on next iteration.

for(int i = 0; i < list.Count; i++){
   if(i == 5)
    i = list.Count;  //it will make "i<list.Count" false and loop will exit
}