Simple comparision question

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Simple comparision question #424539 06/18/13 16:52 06/18/13 16:52
M Malice Unregistered
Malice Unregistered M	The manual says you should not do a Boolean check on a pointer and comp it's member(s) values in the same if(). Is this still true. Example below. Code: if ( pan_temp && pan_temp.pos_x != 1024 ) // The manual says don't do this. if ( pan_temp ) // Manual say do this. { if ( pan_temp.pos_x != 1024 ); } Also does this apply if you are doing the Boolean check on the contents of a VAR and not it's pointer. Code: var I = 999; if ( I && I > 500 )

Re: Simple comparision question [Re: ] #424542 06/18/13 17:15 06/18/13 17:15
Joined: May 2009 Posts: 5,370 Caucasus 3run Senior Expert
3run Senior Expert Joined: May 2009 Posts: 5,370 Caucasus	Why do you need to check 'var' for? If it's not declared, it won't compile anyway, or am I getting your point wrong? Greets Looking for free stuff?? Take a look here: http://badcom.at.ua Support me on: https://boosty.to/3rung

Re: Simple comparision question [Re: 3run] #424546 06/18/13 17:25 06/18/13 17:25
Joined: Jul 2008 Posts: 2,107 Germany rayp X
rayp X Joined: Jul 2008 Posts: 2,107 Germany	Quote: The manual says you should not do a Boolean check on a pointer and comp it's member(s) values in the same if(). Is this still true. Example below. Still true. Maybe in near future it will be changed. Acknex umgibt uns...zwischen Dir, mir, dem Stein dort... "Hey Griswold ... where u gonna put a tree that big ?" 1998 i married my loved wife ... Sheeva from Mortal Kombat, not Evil-Lyn as might have been expected rayp.flags \|= UNTOUCHABLE;

Re: Simple comparision question [Re: rayp] #424548 06/18/13 17:32 06/18/13 17:32
M Malice Unregistered
Malice Unregistered M	@3Run I am checking if the vars content is != 0. Content not pointer. I am trying to see if it has a value not if it was declared. Code: if ( I ) is same as if(I != 0) But I might to totally wrong in my understand of what I did above. @rayp Thank you for this reply. That's is where my code is breaking. Last edited by Malice; 06/18/13 17:34.

Re: Simple comparision question [Re: ] #424549 06/18/13 17:34 06/18/13 17:34
Joined: Jul 2008 Posts: 2,107 Germany rayp X
rayp X Joined: Jul 2008 Posts: 2,107 Germany	Code: if (!i) _empty(); if (i) _notempty(); Do u mean this ? edit: So if (i) should be the same as if (i!=0) yes. Last edited by rayp; 06/18/13 17:35. Acknex umgibt uns...zwischen Dir, mir, dem Stein dort... "Hey Griswold ... where u gonna put a tree that big ?" 1998 i married my loved wife ... Sheeva from Mortal Kombat, not Evil-Lyn as might have been expected rayp.flags \|= UNTOUCHABLE;

Re: Simple comparision question [Re: rayp] #424551 06/18/13 17:36 06/18/13 17:36
M Malice Unregistered
Malice Unregistered M	@rayp Yes that is what I'm asking. Does the same rule apply as pointers here Code: if( i && i != 500) // Bad ? if(i) // Good? { if(i != 500) } I have to stop using i because of autocaps for i Last edited by Malice; 06/18/13 17:38.

Re: Simple comparision question [Re: ] #424554 06/18/13 17:43 06/18/13 17:43
Joined: Jul 2008 Posts: 2,107 Germany rayp X
rayp X Joined: Jul 2008 Posts: 2,107 Germany	no you dont need to check VAR's before. edit: Code: var test = 1; if (test > 0 && test < 2) _test_is_one(); if (!test) _test_is_notone(); ENTITY* test2; if (test2) if (test2.x == 10) ... Last edited by rayp; 06/18/13 17:45. Acknex umgibt uns...zwischen Dir, mir, dem Stein dort... "Hey Griswold ... where u gonna put a tree that big ?" 1998 i married my loved wife ... Sheeva from Mortal Kombat, not Evil-Lyn as might have been expected rayp.flags \|= UNTOUCHABLE;

Re: Simple comparision question [Re: ] #424556 06/18/13 17:48 06/18/13 17:48
Joined: Jun 2009 Posts: 2,210 Bavaria, Germany Kartoffel Expert
Kartoffel Expert Joined: Jun 2009 Posts: 2,210 Bavaria, Germany	The manual says that this is "good" because the program checks the whole comparision before deciding if it is true or false. Code: ENTITY * ent; void main() { if(ent && ent.x > 5) ent.x = 0; } this will result in an error. ent doesn't exist so if you check if(ent) it is true. but in the comparison above the program doesn't abort it but checks the next comparison (ent.x > 5) but ent doesn't exist and this causes an error. edit: note that this only applies for pointers. Last edited by Kartoffel; 06/18/13 17:51. POTATO-MAN saves the day! - Random

Re: Simple comparision question [Re: ] #424557 06/18/13 17:49 06/18/13 17:49
Joined: May 2009 Posts: 5,370 Caucasus 3run Senior Expert
3run Senior Expert Joined: May 2009 Posts: 5,370 Caucasus	Why don't you use something like this: Code: var checkVar(var CHECK){ if(CHECK != 0){ return(1); } if(CHECK == 0){ return(0); } } Hope, it helps Greets Looking for free stuff?? Take a look here: http://badcom.at.ua Support me on: https://boosty.to/3rung

Re: Simple comparision question [Re: ] #424559 06/18/13 17:56 06/18/13 17:56
Joined: Sep 2007 Posts: 101 Luxembourg K krial057 Member
krial057 Member K Joined: Sep 2007 Posts: 101 Luxembourg	EDIT: sorry, only read your first post when i wrote it ^^ Quote: The manual says you should not do a Boolean check on a pointer and comp it's member(s) values in the same if(). Is this still true. Yes. Quote: Also does this apply if you are doing the Boolean check on the contents of a VAR and not it's pointer. It depends of what you want to do. variables in if's evaluate to "false" if they are 0 and to "true" if they are non-zero. Here are some examples: Code: i=10; if(i) -> if(true) -> will execute i = -20; if(i) -> if(true) -> will execute i = 0; if(i) -> if(false) -> will not execute so your second example will work only if I > 500 ("I &&" is useless, because if(i) means if i is not 0. But your second contion I>500 includes that i is not null). Why do you need to check it with poitners in an if? 3dgs evaluates all conditions in the if. If you have something like the following: Code: pan_temp = NULL; if( pan_temp && pan_temp.pos_x != 1024 ) It will evaluate to the following: Code: if(NULL && NULL.pos_x != 1024 ) And because NULL has no property pos_x, the compiler will show an error. Last edited by krial057; 06/18/13 17:56.

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