Do you prefer “if (var)” or “if (var != 0)”? [closed]

Answer 1

I generally prefer if (var) or if ($var) if var is used as a boolean, even if there isn't any such type in the language.

I very much dislike constructs like if (!strcmp(...)) or if (var == true). The first tries to be too smart, the second too dumb -- although it scales well to if ((var == true) == true), ... ;-)

Some languages, like Perl and C++, provide extra or even user defined interpretations of trueness. If the conversion to a boolean seems too magic, remember it's basically just an is_true(var) or var.booleanValue(), or something like that behind the scene, just a more concise syntax.

Related to your question, I like to formulate conditions in a positive way. Instead of

if (!condition) {
    g();
}
else {
    f();
}

I prefer

if (condition) {
    f();
}
else {
    g();
}

Even if there is only a single branch, and the condition is not terribly simple. (An indication for that is the need for a comment.) For example, instead of

// explain reason for condition here
if (!condition) {
    f();
}

I prefer to phrase it as

if (condition) {
    // explain condition here
}
else {
    f();
}

Answer 2

If you have a value that is intended to be a boolean, you should feel comfortable just doing:

if ( var )
if ( $var )

If you have more specific requirements for your "boolean," you can always do some prep work/tests on your variable and assign it to another variable with better defined boolean values.

$shouldDoSomething = ( defined $var and $var ne '' ) ? 1 : 0;

if ( $shouldDoSomething ) {
    // Handle this case.
}

This can clean up the code quite a bit. It also helps if you intend to use this condition more than once. I find this happens pretty frequently, actually. Also, I feel like the above is far more readable than doing it inline:

if ( defined $var and $var ne '' ) {
    // Handle this case.
}

Answer 3

In my opinion, if (var != 0) is better.

Answer 4

I like Python constructions:

if var:
    return "I like the way I do it!"

It's just for example ;-)

Answer 5

To my way of thinking, simplicity is best.

The simpler you make the code, the better. Also, the less likely you'll make mistakes. Therefore, I would use

if(var)

But in the end, you should use what works best for your own way of thinking.

Answer 6

Very often I use:

 if(x) {
       DoSomething;
       DoSomething2;
     }

Because this is less writing, and book which reading said:

Few good programmers use form if(x!=0), they use if(x).

But sometimes use and other form:

if(x!=0) 

HNY! :-)