How do you swap Arrays?

BlitzMax Forums/BlitzMax Beginners Area/How do you swap Arrays?

Kedumba

(Posted 2014) [#1]

Hi,

I am trying to write a function to swap the contents of 2 arrays and for the life of me I can't work what I'm doing wrong. I've tried google but as yet not found anything helpful.

Here is my code:

Local a:Int[6]
Local b:Int[6]

SeedRnd MilliSecs()

' fill array with random stuff
For t=0 To 5
	a[t]=Rnd(1,100)
	b[t]=Rnd(1,100)
Next

'show initial array
show_list(a,b)

' swap arrays
swap(a,b)

' show it again
show_list(a,b)

End


Function show_list:Int(l1:Int[],l2:Int[])

	For t=0 To 5
		Print t + "] " + l1[t] + " | " + l2[t]
	Next
	Print "------------------"
	
End Function
 

Function swap(array1:Int[],array2:Int[])

	Local tmp:Int[6]
	
	tmp = array1
	array1 = array2
	array2 = tmp
		
End Function

Using the debugger, I see that the arrays swap in the "swap" function, however it doesn't seem to affect the original arrays as they don't swap. Any suggestions would be greatly appreciated
thanks

Henri

(Posted 2014) [#2]

Hello,

the parameters in a function are actually copies and operate only in the scope of the function. If you want to manipulate the original arrays just add "Var" after the parameter like;

Function swap(array1:int[] Var, array2:int[] Var)

-Henri

Kedumba

(Posted 2014) [#3]

Thank you Henri
that worked and is exactly what I was looking for.
Thanks again