Style Preferences for Conditional Returns

[Stevens Miller]

I have a routine that returns a boolean. If any of a series of tests fails, the routine returns false, otherwise it returns true. For example, the routine might test for whether or not an integer is both odd and greater than 99, thus:

public boolean oddAndOld(int x)
{
    if (x % 2 == 0)
        return false;

    if (x < 100)
        return false;

    return true;
}

I like the above because it suggests that "true" is the condition that applies if the incoming parameter meets all the required criteria. But I've sometimes seen this style used:

public boolean oddAndOld(int x)
{
    if (x % 2 == 0)
        return false;

    if (x < 100)
        return false;
    else
        return true;
}

I like this less because, among other things, if that last criterion is removed, the "else/return true" must be moved up into the immediately preceding test (or else leave some funny whitespace, depending on how you go about removing the departing "if" statement), but it does avoid suggesting that "return true" is hard-coded (that is, it reinforces that "true" is a conditional return value, not inevitable).

Anyone else have preferences here?

[Tony Docherty]

Personally I'd go with the following:

public boolean oddAndOld(int x)  
{  
    return x % 2 != 0 && x >= 100;  
}  

or if more clarity is required

public boolean oddAndOld(int x)  
{
    boolean odd = x % 2 != 0;
    boolean old = x >= 100;  

    return  odd && old;  
}

[Tony Docherty]

I meant to add that if the choice was just between the two you gave, I'd go with the first one.

[Stevens Miller]

Tony Docherty wrote:Personally I'd go with the following:

    return x % 2 != 0 && x >= 100;

Dear God, man, I'm not programming APL!

Yes, for the purpose of applying the criteria in my example, I might do something like that too. My actual code's criteria are rather more complex than can rationally be put into one line, however. More abtractly, my situation would be expressed thus:

public boolean routine(Object ob)
{
    // One or more independent tests, each of which returns false when met.

    return true;
}

Glad you support my own preference, though. I suppose one could defend it on the basis that it allows for conditional processing when true will be returned:

public boolean routine(Object ob)
{
    // One or more independent tests, each of which returns false when met.

    // Some processing that is only done when we return true.

    return true;
}

Though nothing stops that additional processing from being in the same clause as the "return true" statement as well.

This is just one of those things I need to take to the 'net, as, being a solo coder, there's no one here to ask.