Why is it considered a bad practice to omit curly

Question

Why does everyone tell me writing code like this is a bad practice?

if (foo)
    Bar();

//or

for(int i = 0 i < count; i++)
    Bar(i);

My biggest argument for omitting the curly braces is that it can sometimes be twice as many lines with them. For example, here is some code to paint a glow effect for a label in C#.

using (Brush br = new SolidBrush(Color.FromArgb(15, GlowColor)))
{
    for (int x = 0; x <= GlowAmount; x++)
    {
        for (int y = 0; y <= GlowAmount; y++)
        {
            g.DrawString(Text, this.Font, br, new Point(IconOffset + x, y));
        }
     }
 }
 //versus
using (Brush br = new SolidBrush(Color.FromArgb(15, GlowColor)))
    for (int x = 0; x <= GlowAmount; x++)
        for (int y = 0; y <= GlowAmount; y++)
            g.DrawString(Text, this.Font, br, new Point(IconOffset + x, y));

You can also get the added benefit of chaining usings together without having to indent a million times.

using (Graphics g = Graphics.FromImage(bmp))
{
    using (Brush brush = new SolidBrush(backgroundColor))
    {
        using (Pen pen = new Pen(Color.FromArgb(penColor)))
        {
            //do lots of work
        }
    }
 }
//versus
using (Graphics g = Graphics.FromImage(bmp))
using (Brush brush = new SolidBrush(backgroundColor))
using (Pen pen = new Pen(Color.FromArgb(penColor)))
{
    //do lots of work
}

---

The most common argument for curly braces revolves around maintance programming, and the problems that would ensue by inserting code between the original if statement and its intended result:

if (foo)
    Bar();
    Biz();

---

Questions:

1. Is it wrong to want to use the more compact syntax which the language offers? The people that design these languages are smart, I can't imagine they would put a feature which is always bad to use.
2. Should we or Shouldn't we write code so the lowest common denominator can understand and have no problems working with it?
3. Is there another argument that I'm missing?

Answer 1

I used to be a huge supporter of "curly braces are a MUST!", but since adopting unit testing, I find that my unit tests protect braceless statements from the scenarios like:

if (foo)
    snafu();
    bar();

With good unit tests, I can confidently omit curly braces for simple statements to improve readability (yes, that can be subjective).

Alternatively, for something like the above, I would likely inline that to look like:

if (foo) snafu();

That way, the developer who needs to add bar() to the condition, would be more apt to recognize the lack of curly braces, and add them.

Answer 2

One of the instances where this can bite you is back in the old days of C/C++ macros. I know this is a C# question, but often coding standards carry over without the reasons why the standard was created in the first place.

If you aren't very careful when you create your macros, you can end up causing problems with if statements that don't use the {}.

#define BADLY_MADE_MACRO(x) function1(x); function2(x);

if (myCondition) BADLY_MADE_MACRO(myValue)

Now, don't get me wrong, I'm not saying that you should always do {} just to avoid this problem in C/C++, but I have had to deal with some very strange bugs because of this.

Answer 3

I agree that "if you are smart enough to get someone to pay you to write code, you should be smart enough to not rely solely on indentation to see the flow of the code."

However... mistakes can be made, and this one is a pain to debug... especially if you're coming in looking at someone else's code.

Answer 4

I prefer the clarity that the curly brace offers. You know exactly what is meant and don't have to guess if someone just goofed and left them off (and introduced a bug). The only time I omit them is when I put the if and action on the same line. I don't do that very often either. I actually prefer the whitespace introduced by putting the curly brace on its own line, though from years of K&R C-like programming, ending the line with a brace is a practice I have to work to overcome if the IDE doesn't enforce it for me.

if (condition) action();  // ok by me

if (condition) // normal/standard for me
{
   action();
}

Answer 5

This is not always considered a bad practice. The Mono Project Coding Guidelines suggests not to use curly braces if it's not necessary. The same for the GNU Coding Standards. I think it's a matter of personal taste as always with coding standards.

Answer 6

Lines are cheap. Processor power is cheap. Developer time is very expensive.

As a general rule, unless I am developing some absolutely resource / speed critical application, I would always err on the side of writing code that is

(a) Easy for any other developer to follow what I am doing

(b) Comment specific parts of the code that may need it

(c) Easy to debug if something goes wrong

(d) Easy to modify if it needs to be in future (i.e. adding / removing code)

The speed or academic elegance of the code is secondary to these factors from a Business perspective. This is not to say I set out to write clunky or ugly code, but this is MY order of priority.

By omitting curly braces in most instances, it for me makes (b), (c) and (d) more difficult (note not impossible however). I would say that using curly braces or not has not effect on (a).