Sorting a lift by a field in ascending order

BlitzMax Forums/BlitzMax Beginners Area/Sorting a lift by a field in ascending order

McFox

(Posted 2005) [#1]

Hi !

Can someone exmplain me how to sort the number in ascending order on this exemple :

Global List:TList = CreateList()
Type mytype
	Field value:Int
	Function create:mytype(val:Int)
		Local t:mytype = New mytype
		t.value = val
		Return t
	End Function
End Type
Global object1:mytype
Global object2:mytype
Global object3:mytype
object1 = mytype.Create(12)
object2 = mytype.Create(6)
object3 = mytype.Create(28)

List.AddLast object1
List.AddLast object2
List.AddLast object3

SortList(list,True)

For i:mytype = EachIn list
	Print i.value
Next

McFox

(Posted 2005) [#2]

I whish we can edit title...

a list not a lift

REDi	(Posted 2005) [#3]

Global List:TList = CreateList()

Type mytype

	Field value:Int
	
	Function create:mytype(val:Int)
		Local t:mytype = New mytype
		t.value = val
		ListAddLast(List,t)
		Return t
	End Function
	
	Method Compare:Int(This:Object)
		Return Value - mytype(This).value
	EndMethod
	
End Type

mytype.Create(12)
mytype.Create(6)
mytype.Create(28)
List.Sort(True)

For i:mytype = EachIn list
	Print i.value
Next

REDi	(Posted 2005) [#4]

oh, I see you asked for an exmplanation :), so here goes...

To be able to sort a custom type you need to provide a compare method, this takes an object as its param, you then need to work out if this objects value is less/equal or greater than its instance value, you return <0 if its less, 0 if its equal or >0 if its greater.

Hope that helps.

McFox

(Posted 2005) [#5]

Many thanks Papa Lazarou :) You helped me very much, the TList TLink and TLinkEnum is NOT really very well documented :(