To Do or Not to Do: One Line if Statements and Curly Braces

Question

Duplicate:

Why is it considered a bad practice to omit curly braces?

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Hey folks,

Just curious on your thoughts about the below:

if (someCondition) {
      callSomething();
}

vs.

if (someCondition)
      callSomething();

I only ask this because when I started using refactoring tools, the if without curly braces is what they refactored to. Where I used to work we did this all the time, then I was reading a book, Crockford's awesome JavaScript: The Good Parts, and he was saying removing the curly braces caused more coding errors and really wasn't worth saving the two characters. So I started coding again minus the curly bracket refactor.

Just wondering what you folks all think about this.

Answer 1

The former helps when you have to add a second line (or more) to the if condition later on. So keep `em.

Answer 2

If condition and function name are short enough I usually put them on a single line.

if (someCondition) callSomething();

However, I usually try to avoid both and stick to a more functional style that employs the conditional operator.

int variable = someCondition ? callSomething() : callSomethingElse();

or

int variable = callSomething(someCondition);

with the conditional operator (? :) embedded in callSomething.

Answer 3

if (someCondition)
   if ( someOtherCondition )
      callSomething();
else
   callSomethingElse();

Quick! From a glance at the code, which if does the else associate with?

Answer 4

I always keep the curly braces. Removing them is just asking for trouble, and for no benefit (if you object to typing two more characters, you probably shouldn't be a programmer).

However, I don't have a problem with keeping everything on one line, if there's room. In this case, I'd write it

if (someCondition) { callSomething(); }

Takes up only a single line, but still has the braces so I don't accidentally introduce bugs.

Answer 5

If I have a series of if-conditions in a row I will use the single-line version without curly braces.

if (x) return true;
if (y) return true;
if (z) return true;

If I have a single if-condition I will use curly braces whether it's on one line or not.

if (x) { return true; }

Answer 6

Personally, I'll eliminate the brackets under the following conditions:

• The condition and the action can readably fit on the same line
• The contained action isn't another block (loop, if, etc.)

Otherwise the brackets are always there.

Answer 7

For the most part, it's purely a stylistic choice. Some even use this style to protect themselves from accidentally forgetting about the lack of curly braces:

if (foo) doBar();

However, if abused and used incorrectly, it's possible to make code much more confusing than it has to be:

if (foo)
   if (bar)
      doBaz();
   else if (thing)
      doOtherThing();
else (something)
   doThatThing();

See, that last else block is incorrectly lined up, but without the braces, it's hard to tell.

But in general, as long as you use one-line if statements wisely, I don't see anything wrong with them.

Answer 8

I say use the braces. It makes your code consistent looking and, as already mentioned, the condition may get bigger than one line and you'll need to add them in anyway.

Answer 9

I would recommend always using braces in the case you give, so that you never have to think about whether to add them or not, and you never have to edit them in and out as the code changes.

Answer 10

In the very simple case of:

if (condition)
    oneFunctionHereOnly();

or

if (condition)
   oneFunctionHereOnly();
else
   someotherSingleFunctionHereOnly();

I don't bother with the curlies. For one I find code that places an opening { in same column as its corresponding } much more readable but with that restriction the above code becomes 8 lines instead of 4.

Answer 11

I always put the braces as I believe it adds to maintainability. If I have ...

if( somePredicate )
  doThatThang();

I am always afraid a maintenance programmer will come along and change it to ...

if( somePredicate )
  doThatThang();
  andThatThang();

without adding the brackets. Also, to me, the brackets add a sense of symmetry to the code.

Answer 12

Using the braces is technically "unnecessary" and just fills the code with meaningless empty space. (Empty space in code is very important, but only where it is meaningful)

I use a simple rule. If any statement contains a child scope (if, while, for, etc) then I omit the curly braces only if the statement and its child occupy one line each. (Bearing in mind that I also use a maximum of one statement per line)

That is,

if (condition)
  return;            -- "if" and child scope are 1 line each, no braces

and:

if (condition1 ||
    condition2)      -- "if" occupies more than 1 line, so use braces
{
  return;
}

if (condition)
{
  value = 1;         -- child scope contains more than 1 line, so use braces
  return;
}

if (condition)
{
  // We will return now  -- A comment is still a line, so use braces
  return;
}

This applies regardless of what the lines are (comments, code, etc). That makes the rule very simple to apply, which eliminates any chance of making mistakes.

Note that it is generally recommended that we place the braces at the same indent level, as that symmetry (and the indent) provide a visual confirmation that the code is correctly formed. i.e. You can see that the "shape" of the code is correct, without having to actually read it, so any errors stick out like a sore thumb. By placing the open brace on the end of the if statement, there is no visual symmetry and you have to actually read the code to be sure that the scope is correctly formed.

I've not had a scoping error in over 20 years of programming (C, Java, C++, C#) using these rules.