c++ - How to avoid use of goto and break nested loops efficiently

Question

I'd say that it's a fact that using goto is considered a bad practice when it comes to programming in C/C++.

However, given the following code

for (i = 0; i < N; ++i) 
{
    for (j = 0; j < N; j++) 
    {
        for (k = 0; k < N; ++k) 
        {
            ...
            if (condition)
                goto out;
            ...
        }
    }
}
out:
    ...

I wonder how to achieve the same behavior efficiently not using goto. What i mean is that we could do something like checking condition at the end of every loop, for example, but AFAIK goto will generate just one assembly instruction which will be a jmp. So this is the most efficient way of doing this I can think of.

Is there any other that is considered a good practice? Am I wrong when I say it is considered a bad practice to use goto? If I am, would this be one of those cases where it's good to use it?

Thank you

Answer 1

The (imo) best non-goto version would look something like this:

void calculateStuff()
{
    // Please use better names than this.
    doSomeStuff();
    doLoopyStuff();
    doMoreStuff();
}

void doLoopyStuff()
{
    for (i = 0; i < N; ++i) 
    {
        for (j = 0; j < N; j++) 
        {
            for (k = 0; k < N; ++k) 
            {
                /* do something */

                if (/*condition*/)
                    return; // Intuitive control flow without goto

                /* do something */
            }
        }
    }
}

Splitting this up is also probably a good idea because it helps you keep your functions short, your code readable (if you name the functions better than I did) and dependencies low.