Objective-C

if( while ) switch{ coding } ++ — Page [1]

molkman
Owner of George Washington's Prototype Mittens

2005 May 2 • 2066
404 ₧

Okay, I'm trying to get a little into C stuff since it's required for iOS programming. But I don't really get the writing formalities yet. This is probably an easy question, ha.

For example this code:

  code
BOOL trueOrFalse = YES;
if (trueOrFalse)
      NSLog(@"trueOrFalse is true.")
if (1)
      NSLog(@"1 is considered to be true.");

What does if (trueOrFalse) check here? Is it basically like, "if trueOrFalse is yes" or what does the "if" relate to? I mean, it doesn't say "if(trueOrFales == YES)", but instead just the variable. :O

And does the if(1) the same as if(trueOrFalse == 1)?

LET LOVE REIGN

≡

2011 Mar 17 at 20:12 UTC — Ed. 2011 Mar 17 at 20:13 UTC

Down Rodeo
Cap'n Moth of the Firehouse

2007 Oct 19 • 5486
57,583 ₧

It's the same as many languages. Think about what if(true) or if(false) might mean - basically, that is the end comparison that is made. Say you have

  code
if(expr_1 && expr_2) { doSomething(); }

For argument's sake say expr_1 is true and expr_2 is false. You then get

  code
if(true && false)

which is

  code
if(false)

which means the if statement won't execute. Now, there are exceptions and modifications to this, but this is the basic way to think about it. While you can add if(something == true) to an if block there is no particular need but that can aid readability and help catch errors quickly.

This is why I never do the latter, I love errors.

I give a little into the moment like I'm standing at the edge (I know)
That no-one's gonna turn me 'round
Just one more step, I could let go

≡

2011 Mar 17 at 20:45 UTC

molkman
Owner of George Washington's Prototype Mittens

2005 May 2 • 2066
404 ₧

Okay.

So if I have

  code
if(variable){
    party()
}

it basically does check if the variable is true and then does something, so it's the same as if(variable == true)?

And would

  code
if(!variable){
    party()
}

check if the variable is false? Or can I only use !s with =s?

LET LOVE REIGN

≡

2011 Mar 17 at 21:10 UTC — Ed. 2011 Mar 17 at 21:18 UTC

SuperJer
Websiteman

2005 Mar 21 • 6666

Think of everything in terms of expressions. An expression is either true or false. When you give an if(...) a true expression, it will succeed.

!variable will do exactly what you want.

If variable is true, then !variable is false and vice versa.

≡

2011 Mar 17 at 21:13 UTC — Ed. 2011 Mar 17 at 21:17 UTC

molkman
Owner of George Washington's Prototype Mittens

2005 May 2 • 2066
404 ₧

Okay, cool. Thanks alot.

LET LOVE REIGN

≡

2011 Mar 17 at 21:19 UTC

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