The deception of C++'s 'continue' and 'break'

Pick up any C++ reference book, visit any C++ web site, and you will see that the 'continue' and 'break' keywords are grouped with the loop constructs. In many ways it makes sense, since you can use these keywords with only those constructs.

But the more I think about 'continue' and 'break', the more I realize that they are not loop constructs. Yes, they are closely associated with 'while' and 'for' and 'case' statements, but they are not really loop constructs.

Instead, 'continue' and 'break' are variations on a different construct: the 'goto' keyword.

The 'continue' and 'break' statements in loops bypass blocks of code. 'continue' transfers control to the end of the loop block and allows the next iteration to continue. 'break' transfers control to the end of the loop block and forces the loop to end (allowing code after the loop to execute). These are not loop operations but 'transfer of control' operations, or 'goto' operations.

Now, modern programmers have declared that 'goto' operations are evil and must never, ever be used. Therefore, 'continue' and 'break', as 'goto' in disguise, are evil and must never, ever be used.

(The 'break' keyword can be used in 'switch/case' statements, however. In that context, a 'goto' is exactly the construct that we want.)

Back to 'continue' and 'break'.

If 'continue' and 'break' are merely cloaked forms of 'goto', then we should strive to avoid their use. We should seek out the use of 'continue' and 'break' in loops and re-factor the code to remove them.

I will be looking at code in this light, and searching for the 'continue' and 'break' keywords. When working on systems, I will make their removal one of my metrics for the improvement of the code.