Strange things about moving object

I think i have individuated the error!!!
I have to declare the variable that control the angle INTO the type!
Else at every call to a function the angle sum itself with the precedent angle...argh
Here's the correct function:

Type alieno
	Field posizionex#
	Field posizioney#
	Field velocita#
	Field percorso
	Field angolo#
End Type
Function crea_alieno(xpos,ypos,speed,movimento)
	a.alieno=New alieno
	a\posizionex=xpos
	a\posizioney=ypos
	a\velocita#=speed
	a\percorso=movimento
	a\angolo=0					;new entry!!!
End Function

Function muovi_alieno()
	For a.alieno=Each alieno
		Select a\percorso
			Case 1
			circleMov()
			Case 2
			strightMov()
			Case 3
			updownMov()
		End Select
	Next
End Function

Global a.alieno






Const scrX=640,scrY=480
;------------------------------------
;Global r1#,r2#,r3#
;------------------------------------
;setup
Graphics scrX,scrY,32,2
SetBuffer BackBuffer()
;------------------------------------
AutoMidHandle True 
;loadgrafx
Global backGnd=LoadImage("go.bmp")
Global enemys=LoadImage("enemy.bmp")
;------------------------------------

;loop
;crea_alieno(100,300,4,1)
;crea_alieno(15,15,1,1)

While Not KeyDown(1)
If MouseHit(1)=True
crea_alieno(50,50,1,1)
crea_alieno(200,400,1,1)
crea_alieno(200,200,2,2)
crea_alieno(100,100,4,3)
EndIf
Cls
TileImage backGnd,ixTim,iyTim 
muovi_alieno()

Flip
Wend
End
;Circle Motion
Function circleMov()
	xpos#=a\posizionex+Sin(a\angolo)*100 
	ypos#=a\posizioney+Cos(a\angolo)*100
	speed1#=a\velocita
	DrawImage enemys,xpos,ypos
	a\angolo=a\angolo+speed1#
	If a\angolo=>359 Then a\angolo=0
End Function
;------------------------------------
;Forward & Backward Motion
Function strightMov()
	xpos#=a\posizionex+Sin(a\angolo)*100
	ypos#=a\posizioney
	speed2#=a\velocita
	DrawImage enemys,xpos#,ypos#
	a\angolo=a\angolo+speed2#
	If a\angolo=>359 Then a\angolo=0
End Function
;------------------------------------
;Up & Down Motion
Function updownMov()
	xpos#=a\posizionex
	ypos#=a\posizioney+Cos(a\angolo)*100
	speed3#=a\velocita
	DrawImage enemys,xpos#,ypos#
	a\angolo=a\angolo+speed3#
	If a\angolo=>359 Then a\angolo=0
End Function

(a question:what's the forum command to highlight the code in green?)

(edited:i have found the command :P )

I hope that is the definitive version.