Which way do you prefer, and why?

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=PRoF=

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Posted: 14th Jun 2015 23:14

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Hi Guys,

I find myself spending far too much time wondering which one of these two methods is the best, and why?

What I am doing is using a pair of Booleans to decide which one of four actions to perform.

Method 1:

+ Code Snippet

If a=0 and b=0
	
	//	Do action 1
	
Endif

If a=0 and b=1
	
	//	Do action 2
	
Endif

If a=1 and b=0
	
	//	Do action 3
	
Endif

If a=1 and b=1
	
	//	Do action 4
	
Endif

This method is neater and easier to follow, but seems kind of long winded.

Method 2:

+ Code Snippet

If a=0
	
	If b=0
		
		//	Do action 1
		
	Else
		
		//	Do action 2
		
	Endif
	
Else
	
	If b=0
		
		//	Do action 3
		
	Else
		
		//	Do action 4
		
	Endif
	
Endif

This method is less easy to follow, but I think is a lot more efficient in that it doesn't cause the computer to evaluate so many conditions.

So I thought I'd throw it out here and see what you guys had to say? or if you had any better way of doing it which I hadn't thought of...

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Zwarteziel

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Posted: 15th Jun 2015 09:03 Edited at: 15th Jun 2015 09:13

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I always try to use the method that involves the least computation. Regarding the selection of conditions, you might want to look into the select-endselect and case-endcase statements AppGameKit provides: with them, you can create code that is both easy to read and efficient to execute.

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baxslash

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Posted: 15th Jun 2015 09:34 Edited at: 15th Jun 2015 09:38

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Elaborating on Zerotown's suggestion, if you use integers for your bools anyway why not assign different values to each. 0 is still false but any other number can be true so:

+ Code Snippet

if aTrue=1
    a=1
else
    a=0
endif

if bTrue=1
    b=2
else
    b=0
endif

select a+b
    case 0
        // a and b are both false
        
    endcase
    case 1
        // a is true but b is false
        
    endcase
    case 2
        // a is false but b is true
        
    endcase
    case 3
        // a and b are true
        
    endcase
endselect

Effectively you reduce 4 conditions to just 1. From your 2 examples Method 2 does less conditions than Method 1 but a single case statement is much quicker.

Using AppGameKit V2 Tier 1

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Impetus73

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Location: Volda, Norway

Posted: 15th Jun 2015 10:08 Edited at: 15th Jun 2015 10:08

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Another variant:

+ Code Snippet

select a
    case 0
        if b=0
	    // Do action 1
        else
            // Do action 2
        endif
    endcase
    case 1
        if b=0
	    // Do action 3
        else
            // Do action 4
        endif
    endcase
endselect

----------------
AGK programmer
Did Amiga / AMOS programming in the 90's.

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BatVink

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Posted: 15th Jun 2015 11:55

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I would go with Baxslash's solution

Quidquid latine dictum sit, altum sonatur
TutCity is being rebuilt

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Impetus73

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Posted: 15th Jun 2015 12:45

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I think Baxslash's code can be optimized:

+ Code Snippet

if aTrue=1
    a=1
else
    a=0
endif

if bTrue=1
    b=2
else
    b=0
endif

select a+b

Can be changed to:

+ Code Snippet

select a+(b*2)

----------------
AGK programmer
Did Amiga / AMOS programming in the 90's.

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baxslash

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Posted: 15th Jun 2015 14:18

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Clever! I like it Impetus73!!

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=PRoF=

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Posted: 15th Jun 2015 23:29 Edited at: 16th Jun 2015 01:03

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@Zerotown:
I'm well aware of the select/case commands, but I hadn't thought of a way of using 2 variables with one.

@Baxslash:
AGK doesn't have a proper Boolean data type does it? I'm sure it never used to, but AGK2 has a way of sneaking surprise new things on me. I was blown away by he new array system which I didn't discover until about a fortnight ago.

>Edit<
Completely forgot to say thanks for the snippet. I've used it with Impetus73's alteration.

@Impetus73:
Yeah, that's how I probably would have done it if I was originally using a select/case block.

@BatVink:
I have

@Impetus73(again):
That's really cool. I have used that.

Thanks guys, as always.

It's always nice to see how other ppl code things

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DavidAGK

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Posted: 15th Jun 2015 23:30

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I did a test a while back on nesting multiple conditions versus using and's in larger but less nested conditions and was surprised by how little difference performance wise it made. I was expecting the deeper nested conditions to win hands down as computation is stopped early in some cases.

Using Tier 1 AppGameKit V2
Started coding with AMOS (Thanks Francois Lionet)

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Scraggle

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Posted: 15th Jun 2015 23:39 Edited at: 15th Jun 2015 23:40

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Nice Impetus, very nice!

I love this kind of question and the answers that they produce

AGK V2 user - Tier 1 (mostly)

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BatVink

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Posted: 16th Jun 2015 10:43

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Another nifty one for toggling a switch between -1 and 1. Many people use 0 and 1, but it can be any 2 numbers and 1 / -1 works...

I always used:

+ Code Snippet

if a = 1
   a = -1
else
   a = 1
endif

This can be replaced by 1 line of code...

+ Code Snippet

a = 0 - a

Quidquid latine dictum sit, altum sonatur
TutCity is being rebuilt

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baxslash

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Posted: 16th Jun 2015 12:27

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I tend to toggle between 0 and 1:
a = 1 - a

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Scraggle

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Posted: 16th Jun 2015 12:36 Edited at: 16th Jun 2015 12:36

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I often use the same booleans as BatVink (1 and -1), so here is a random generator for those:

+ Code Snippet

random(0,1)*2)-1

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Impetus73

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Posted: 16th Jun 2015 13:23

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To change any value to the opposite:

+ Code Snippet

xspeed = xspeed *-1

----------------
AGK programmer
Did Amiga / AMOS programming in the 90's.

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Sph!nx

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Posted: 16th Jun 2015 16:26

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Great topic. Got nothing to add than that I've learned from it!

Regards Sph!nx

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baxslash

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Posted: 16th Jun 2015 17:55 Edited at: 16th Jun 2015 17:56

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Quote: "I often use the same booleans as BatVink (1 and -1), so here is a random generator for those:
"

RandomSign(1)

Quote: "To change any value to the opposite:
"

value = -value

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Yodaman Jer

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Posted: 17th Jun 2015 00:13

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If AppGameKit had proper booleans (actually using the words "true" and "false"), one could flip any boolean like so:

If GetPointerPressed(1) = 1 then booleanValue = !booleanValue

I used to do that in Unity all the time when I needed something that could be toggled. A nice little shortcut! Impetus' technique of

value = value * -1
is the workaround for AppGameKit that I have used.

Think YodamanJer, Think Clonkex, GAIN POINTS!

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=PRoF=

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Posted: 17th Jun 2015 00:46

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@Yodaman Jer:
As part of the system module for my Game Template, I have these handy constants defined...

+ Code Snippet

//  System Constants
#Constant True 1
#Constant False 0
#Constant Fail -1

I find they certainly help avoiding using arbitrary numbers. I use the Fail value mostly as a return from functions which have failed for whatever reason.

It's really annoying when I start to write a small snippet for whatever reason, I always forget that True/False aren't proper AppGameKit commands.

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Jambo B

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Posted: 22nd Jun 2015 23:12

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Quoting Baxslash:

Quote: "Effectively you reduce 4 conditions to just 1. From your 2 examples Method 2 does less conditions than Method 1 but a single case statement is much quicker."

Kind of on a related note - is it still true that with case statements you should put the most-used statement at the top, to speed up processing? Theory is that the other case statements still need to be evaluated, so the least-used case would be at the end.

Or does AppGameKit do something nifty of which I'm not aware, to avoid checking every case?

- James

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Yodaman Jer

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Posted: 23rd Jun 2015 02:23 Edited at: 23rd Jun 2015 02:24

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Quote: "value = -value"

...How did I never realize that would do exactly the same thing as value = value *-1?

Hey it is true, you do learn something new each and every day!

Official Forum President from June 20th, 2015 - June 20th, 2016 (when my successor is elected, whomever that may be!).

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SoftMotion3D

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Posted: 24th Jun 2015 04:21 Edited at: 24th Jun 2015 04:25

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Quote: "xspeed = xspeed *-1"

Quote: "value = -value"

omg....lol

i made a function that took the value and subtracted it twice to produce the negative value and took the abs(#) of it if it was negative to start with....lol

thanks for the quicker code! (no function required anymore!)

www.sheldonscreations.com

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