break and continue in a loop enclosed switch block

Question

So I have some C# code that looks like this:

while(condition)
{
    switch(anumber)
    {
        case 0:
            //do something
            break;
        case 1:
            //do something
            break;
        //and so on
    }
}

Being a noob at programming, I recently added the keyword continue to my vocabulary. After doing some research I came across this:

the continue statement relates to the enclosing loop

So my code should work like this as well:

while(condition)
{
    switch(anumber)
    {
        case 0:
            //do something
            continue;
        //and so on
    }
}

But writing code that just gives no compiler error is not everything. Is using continue in a loop enclosed switch block a good idea? Is there any difference in, for example, performance or are these just two syntactically different but otherwise quite similar ways to achieve the same result?

First, it is syntactically correct. Talking about an idea, in general - it is not a sort of bad practice to use `continue` within a `switch` statement. However, it worsens readbility and compilcates debugging and I wouldn't use it. `continue` belongs to `while`, and therefore destroys the structure nesting. Moreover, if you only have `switch` within this loop, then you don't need this `conitnue` at all. `break` will provide the same behaviour, since there are no other statements. — Yeldar Kurmangaliyev, Nov 23 '15 at 09:20

score 5 · Accepted Answer · answered Nov 23 '15 at 09:18

5

If there are some lines of code after the switch, continue keyword will ignore them. Try this and you will see the different:

while(condition)
{
    switch(anumber)
    {
        case 0:
            //do something
            break;
        case 1:
            //do something
            break;
        //and so on
    }
    Console.WriteLine("it's a message");
}

and

while(condition)
{
    switch(anumber)
    {
        case 0:
            //do something
            continue;
        case 1:
            //do something
            continue;
        //and so on
    }
    Console.WriteLine("it's a message");
}

answered Nov 23 '15 at 09:18

tdat00

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There is a big difference between break and continue in your examples. If you look at carefully at the first example break is a part of switch statement. In the second example continue is a part of while loop. In the first example break is matched with every case and in the second example continue is matched with while loop. – MistyK Nov 23 '15 at 09:20
3

Yes, I know that. I just want to show the different to OP. – tdat00 Nov 23 '15 at 09:22
Also, if continue and break are both used, this might be confusing because they are not referring to the same structure, as they usually would be. – JSQuareD Nov 23 '15 at 09:23
You're right, I totally didn't think of that. But I think I'll stick with the break for the sake of readability if that's the only difference in behaviour. – Wilsu Nov 23 '15 at 09:27
A switch statement is not a loop, When you code the Continue keyword in a switch statement block it relates to the loop which encloses the switch statement. In short when you use the key word continue it restarts the loop currently being interpreted. – Needham Nov 23 '15 at 09:35

score 0 · Answer 2 · answered Jan 20 '22 at 11:42

https://stackoverflow.com/a/20019538/187650

The continue statement is related to break, but less often used; it causes the next iteration of the enclosing for, while, or do loop to begin. In the while and do, this means that the test part is executed immediately; in the for, control passes to the increment step.

The continue statement applies only to loops, not to a switch statement. A continue inside a switch inside a loop causes the next loop iteration.

This above is for C++ but in case of C# if you debug in Visual Studio you will see also a difference when pressing F10.

When debugging the break statement it will first go to the closing '}' tag of the switch statement before going to the while/for-loop.

In case of continue, the closing '}' tag of the switch statement will not be hit and it will go directly to the while/for-loop to continue the next iteration.

break and continue in a loop enclosed switch block

2 Answers2