Question

I saw a similar piece of perl code in the code base and wanted to know if this (setting i=100) was an OK way to get out of the for loop? Are there any pitfalls to this?

int a[100];

...

bool check_if_array_contains_29()
{
    bool result = false;
    for(int i=0; i<100; ++i)
    {
        if(a[i] == 29)
        {
            result = true;
            i = 101;
        }
    }
    return result;
}

This is more like what I would do.

bool check_if_array_contains_29()
{
    bool result = false;
    for(int i=0; i<100 && !result; ++i)
    {
        if(a[i] == 29)
        {
            result = true;
        }
    }
    return result;
}

Edit -1:

I am not looking for a oneliner in perl to achieve the functionality. The real code (functionality) was much more complex. This is just an example that I simplified to explain my point(early termination of for loop).

Answer 1

Why wouldn’t you just do this:

bool check_if_array_contains_29()
{
    for(int i=0; i < 100; ++i)
    {
         if (a[i] == 29)
           return true;
    }
    return false;
}

Edit:
I know some people feel that multiple return statements are just horrible and should be avoided at all costs, but to me, having multiple returns in a method like the one presented makes the code easier to read and follow.

Edit 2:
Additional versions so that if the method needs to have some side effects or perform some additional operations you can use a break statement, or you can adjust the for loop conditional, or you could add some labels and some gotos.

bool check_if_array_contains_29_take2()
{
    bool result = false;
    for (int i=0; i < 100; ++i)
    {
        if (a[i] == 29)
        {
            result = true;
            break;
        }
    }

    // Do Other Stuff
    return result;
}

bool check_if_array_contains_29_take3()
{
    bool result = false;
    for (int i=0; !result && i < 100; ++i)
    {
        result = a[i] == 29;
    }

    // Do Other Stuff
    return result;
}

// Special edition for those who can't get enough goto
bool check_if_array_contains_29_and_do_more_stuff_without_early_return()
{
    bool result = false;
    for (int i=0; i < 100; ++i)
    {
        if (a[i] == 29)
        {
            result = true;
            break;
        }
    }

    if (!result)
        goto error;

    // Do some other stuff in the code here
    goto done;

done:
    return result;
error:
    result = false;
    goto done;
}