Are singleline if statements or if statements without braces bad practice?

Question

if (condition) { /* do something */ }
else { /* do something */ }

if (condition)
    /* do something */
else
    /* do something */

I was told tha

Answer 1

For all but the shortest statements, use the braces and space them accordingly. You want to do this for a few reasons:

• It's harder to make a mistake about where something goes.

• It's easier to read.

• In languages with macro-expansion facilities (e.g. C, C++), failure to include braces will cause confusing logic errors when a macro containing multiple statements is expanded inside of an unbraced if-else.

Answer 2

You should put the "if" and the "do something" on separate lines to make your code friendlier to interactive debuggers.

If you put both the "if" and "do something" on the same line, then you can't set a breakpoint just on the "do something" line.

Answer 3

The best practice is to write code that others can read and update easily.

Your first form is questionable because it doesn't follow the forms that most PHP developers are used to:

if (condition) {
  // code
} else {
  // code
}

// ... or ...

if (condition)
{
  // code
}
else
{
  // code
}

// ... or ...

if (condition) { /* short code */ } else { /* short code */ }

// ... or ...

condition ? /* short code */ : /* short code */;

Note that this is entirely about standard practice, and doesn't necessarily make sense—it's only about what other developers are used to seeing.

Your second form, more importantly, isn't so good because it makes it easy for another programmer to make this mistake:

if (condition)
  // code A
else
  // code B
  // code C (added by another programmer)

In this example, the other programmer added code C, but forgot to wrap the whole else block in braces. This will cause problems. You can defend against this by simply wrapping your if and else blocks in braces.

Answer 4

My preference if for consistency... so:

if(...)
{
   statement 1;
   statement 2;
}
else
{
   statement 1;
   statement 2;
}

is no different than:

if(...)
{
   statement 1;
}
else
{
   statement 1;
}

So I always use them because it is consistent and it avoids problems forgetting to add them in later.

However other people will look at my code and think that it is stupid to put in the { and }. They have their reasons, I have mine... I happen to like my reasons more than I like theirs :-)

Answer 5

This is more coding style than anything else. That said, my personal opinion is that your second example is potentially quite harmful. It's easy enough to accidentally "add a second line to the block" in languages where braces are the only way to create blocks. But in PHP, where an alternate syntax exists, this is even less likely to set off the necessary warning bells:

if ($_GET["asdf"]==1):
    /* do something */
else:
    /* do something */
endif;

Rule of thumb: if you're going to put your "do something" on a separate line, use braces; if you're not going to use braces, put it on the same line!

Answer 6

This is something that I actually remember from an employment exam a while back. The code was similar to the following:

if (x == 0)
    x = 2;
else
    print("x is: %d", x); // debugging!
    x = 4;

Most people here can spot the error, but you can really substitute in anything you want as the "bad code" that was inserted. The more subtle error comes when you have an "old version" of something commented out, and somebody un-comments it, and suddenly the second statement is outside the block.

Basically, unless it's a small test application to learn a concept fast, I always bracket (and even in the test apps I usually bracket). It just isn't worth the headache later if I don't, even in 5-line-methods.