Thread: Simple syntax habit, good or bad...

Nice little low level opinion question for all the experienced coders who have worked with a lot of other programmers in their careers...

I've been writing a certain syntax with conditionals and loops for quite a while and I've found now that not many people do it. Let me show you what it looks like and tell me if you personally have a problem with it as a programmer. It's perfectly legal, however it may seem slightly obscure.

Code:

if(/*condition*/)
   // Do something
else while(/*NOT condition*/) {
   // Do some other stuff
}

I recently had a teacher tell me that "else while" isn't an actual control structure and I explained I understood, I just write it like that out of habit. Anyone think it's wrong and I should change it? It really is the simplest of code and I don't personally see anything wrong with it. In fact, it seems more logical to me to group it that way.

I don't like it. It makes it seem as though this:

Code:

else while(...)...

is different from this:

Code:

else
{
     while (...)
     { ....
     }
}

Also, it makes your code somewhat less readable.

Originally Posted by manutd

I don't like it. It makes it seem as though this:

Code:

else while(...)...

is different from this:

Code:

else
{
     while (...)
     { ....
     }
}

Also, it makes your code somewhat less readable.

I think your first remark was the way my teacher felt, as well. I assumed, though, that any experienced programmer would know there is no difference between the two and would simply consider it a formatting style as it is. However, I do respect you opinion on readability. I do encourage you, though, to read a similar plain English statement and reread the code. For example:

If the cake batter is a yellow color, pour evenly though out the cake dish. Otherwise, continue to beat the batter until it reaches a yellow tone.

Now consider this code:

Code:

// Assume cakeBatter as an instance of a food class with the appropriate methods and variables
// and assume cbYELLOW and pEVENLY are members of their respective enums
if(cakeBatter.color == cbYELLOW)
   pourInDish(cakeBatter, pEVENLY);
else while (cakeBatter.color != cbYELLOW) {
   cakeBatter.beat();
}

You see? Doesn't the "else while" seem appropriate there?

In English, it does. However, most English speakers would be considered "advanced English programmers". As not ever beginning programmer might know that this is not a new type of loop, they might get freaked out and try to find an example of how to use it on the internet. Thus for consistency, I like the second way. Also, the braces/indentation show more clearly the program flow. But that's just my opinion. You may have your entirely different (but still valid) style.

>Anyone think it's wrong and I should change it?
I don't think it's wrong, but I do think that you should consider its usage carefully. When people read code, they expect certain styles and conventions. If you deviate from those styles and conventions, you tend to make your code harder to follow.

It doesn't shock me. I'm used to do things like:

Code:

if (this) do_this;
else for (...) {
        do_that_;
        and_do_that_too;
    }

Also,

Code:

if (this) do_this; else do_that;

Confessedly, I don't try to be smart around much bigger pieces of code at which time I do "proper" indentation. But if I can avoid curly braces around small snippets, I do.

With me, if it's a one line thing:

Code:

if (/*condition*/) dosomething();

I use it, but when combined with loops, etc, I use curly braces as they make execution more clear to me.

Code:

if(/*condition*/)
   // Do something
else while(/*NOT condition*/) {
   // Do some other stuff
}

Are the conditions above the same, with one simply the NOT of the other? If yes, then it seems like a logical grouping you've constructed, and I don't have a problem with it. If no, then I'm not as enthused about the grouping.

One of the guidelines I subscribe to is full bracing, always*. So your preference goes against my habit.
[voice="Forest Gump"]And that's about all I've got to say about thaaat.[/voice.]

*Except in some initializations, but always in program structure.

There is no good reason to use 'else while'. There is a good reason for 'else if': for chaining them along when a switch would not work. You cannot chain while loops. I can't think of a plausible way that this could improve readability.

Other than perhaps for the one who reads and maintains his own code, and because of some wicked gene does find it readable?

You know, the construct itself really isn't that problematic. At first seeing it is a bit odd, but that's really just a matter of rarity.

The main problem with this is that it's hard to imagine a situation where that kind of code idiom would logically be used. Taking, for example, the cake example.

Code:

// Assume cakeBatter as an instance of a food class with the appropriate methods and variables
// and assume cbYELLOW and pEVENLY are members of their respective enums
while (cakeBatter.color != cbYELLOW) {
   cakeBatter.beat()
}
pourInDish(cakeBatter, pEVENLY);

I'd probably do this:

Code:

if(/*condition*/)
   // Do something
else 
   while(/*NOT condition*/) {
      // Do some other stuff
   }

After thinking about it, the most important argument to me against this construct is my expectation when not reading carefully. A condition on the same line as an "else" belongs to an "else if", that's just a given for most programmers, which might cause them to miss the little "while" there. In other words, they read the start of the line ("else") and the end of the line (a condition) and their brain fills in what's between ("if").
And then comes the confusion.

>One of the guidelines I subscribe to is full bracing, always*.
I did that at first, but now I omit braces if the body of a block is only a single line. So I would do this:

Code:

if ( condition )
  foo();

Instead of this:

Code:

if ( condition ) {
  foo();
}

But I make sure to do this:

Code:

if ( condition ) {
  while ( condition )
    foo();
}

Rather than this:

Code:

if ( condition )
  while ( condition )
    foo();

Because the latter isn't translated correctly with most automatic indentation software. Then again, a lot of my personal style consists of "do what I say and not what I do".