Different ways of writing the "if" statement

Question

I have seen different ways of writing an if statement.

Which one do you prefer and why?

Example 1:

if (val % 2 == 1){output = “Number is odd”;}else{output = “Number is even”;} 

Example 2:

if (val % 2 == 1)
{
    output = “Number is odd”;
}
else
{
   output = “Number is even”;
}

Example 3:

if (val % 2 == 1)
output = “Number is odd”;
else
output = “Number is even”;

Example 4:

if (val % 2 == 1){
output = “Number is odd”;
} else {
output = “Number is even”;
}

Similar question:

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

Answer 1

For cases like this, there's also the conditional operator:

output = (val % 2 == 1) ? "Number is odd" : "Number is even";

If you're definitely going to use an "if" I'd use version 2 or version 4, depending on the rest of your bracing style. (At work I use 4; for personal projects I use 2.) The main thing is that there are braces even around single statements.

BTW, for testing parity it's slightly quicker to use:

if ((val & 1) == 1)

Answer 2

Version 2. I always include the brackets because if you ever need to put more than one line under the conditional you won't have to worry about putting the brackets in at a later date. That, and it makes sure that ALL of your if statements have the same structure which helps when you're scanning code for a certain if statement.

Answer 3

I use version 2.

One reason to use curly braces becomes more clear if you don't have an else.

if(SomeCondition)
{
  DoSomething();
}

If you then need to add another line of code, you are less likely to have an issue:

if(SomeCondition)
{ 
  DoSomething();
  DoSomethingElse();
}

Without the braces you might have done this:

if(SomeCondition)
   DoSomething();
   DoSomethingElse();

Answer 4

I personally prefer 3. The extra curly braces just add too much unnecessary visual noise and whitespace.

I can somewhat see the reasoning for 2/4 to reduce bugs, but I have personally never had a bug because thinking extra lines were inside an if statement. I do use C# and visual studio so my code always stays pretty well formatted. This could however be a problem if I was a more notepad style programmer.

Answer 5

I prefer #2. Easy readability.

Answer 6

None of the above.

If my execution block only has one line (even if it's a huge for statement) then I don't use braces, but I do indent it, similar to #3

if (num > 3)
     print "num is greater than 3";
else
     print "num is not greater than 3";

An example with multiple statements that do not need curly braces:

if (num > 3)
    for (int i = 0; i < 100)
        print i + "\n";
else
    print "booya!";

That said, Jon Skeet's response in this question is the best

Answer 7

It is more important to be consistent than to select the best.

These styles have different advantages and drawbacks, but none is as bad as mixing them within a project or even a compilation unit or within a function.

---

Ternary operator is the obvious choice for this specific code. For simple single statement if/else's that can't be otherwise expressed, I'd prefer a properly indented case 3:

if (val % 2 == 1)
    output = “Number is odd”;
else
    output = “Number is even”;

I understand the motivation behind "always use braces", but I've personally never been bitten by their omission (OK, once. With a macro.)

From the above styles, I'd pick (2). (4) would be ok if "properly" indented.
(1) I'd attribute to a young developer who hopefully will grow out of "compact code", or someone who can't afford a decent monitor. Still, I'd go with it if it was the local style.

Answer 8

I use version 2.

Answer 9

I agree with the ternary operator. Very under utilized in code that I come across, and I think it is much easier and nicer to read than all the extra brackets and indents it takes to write out an if/else statement.

Answer 10

It's strange that nobody mentioned this:

if ( x == 1) {
   ...
}
else {
   ...
}

To me, this is the only correct way, of course :-)

Answer 11

I prefer 4 myself, but I think 2 is definitely good too.

Answer 12

Personally, there are two methods that I find being good-practice:

For if-blocks, there's only this way:

if(...)
{
    // ...
}
else if (...)
{
    // ...
}
else
{
    // ...
}

This is the safest and most comprehensible way to write if-else-blocks.

For one liners (true one liners that are comprehensible on one line), you can use the ternary operator.

var objectInstance = condition ? foo : bar;

// Or the binary operator when dealing with null values
var objectInstance = condition ?? foo;

You shouldn't call methods that do something that do not help the current assignation.

I wouldn't use any other way than those stated above.

Answer 13

Version #2 for me - easiest to see, easiest to read, easy to see where the if starts and ends, same for else, you dont have to worry about putting in brackets if you want to add more than one statement.

Answer 14

using with the braces is suggested, I have seen some issue with the if else statement without braces ,(I don't remember exactly) i.e. Statement under if was not executed, when I added the same with braces then only worked.( Using Visual studio & C#4.0).

Answer 15

Example 2 is without a doubt the least error prone approach. Please see this answer I gave to a similar question for the reason why:

What is the prefered style for single decision and action statements?

Although the Visual Studio default for brace usage is to put braces on a newline (my preferred method), the Framework Design Guidelines book (first edition) by Krzysztof Cwalina and Brad Abrams propose a different convention, example 4, placing the opening brace at the end of a preceding if statement (Page 274). They also state "Avoid omitting braces, even if the language allows it".

Not having the second edition at hand, I couldn't say if these conventions have changed or not.

Answer 16

I would use them in the following order: 1) the Ternary operator 2) example 3, but indented properly 3) either 2 or 4, they are basically the same. I would go with whatever the general styl was where I worked.

I agree with what jake said about omitting the unnecessary curly braces. I have never caused or seen a bug caused by new code being added and someone thinking they were part of an if statement but they weren't because of the lack of curly braces. If someone ever did do that, I would ridicule them mercilessly.

You'd have to torture me to get me to use number 1.

Answer 17

I'd always use #2. #4 is a truly awful layout and would only be done by someone who believes that a method must be one screen size in length and will do anything to cram it in, rather than refactor the code!!!

Answer 18

Personally I prefer version 2. But since it's only formating it doesn't matter. Use which is best readable for you and your team members!

Answer 19

I use a #2 with a minor change

if (condition1) 
{
      doStuff();
} else 
{
      doSomethingElse();
}

Answer 20

Single short statements:

if (condition) output = firstChoice;
else doSomethingElse();

Multiple or long statements

if (condition) {
   output = firstChoice;
   ...
} else {
   ...
}