Attempting for multiple screen get ended with a bug

[Petr]

i tried to take pictures from the screen. The behavior of the program is very strange.

As output should be a few screenshots. But it not work. WHY?

Code: QB64: [Select]

1. t# = TIMER
2. DO UNTIL a = 3
3.     PRINT a ' :beep  BEEP WORK
4.     IF TIMER > t# + 1 THEN
5.         scr(a) = _NEWIMAGE(640, 480, 32)
6.         e = _SCREENIMAGE
7.         PRINT e: BEEP 'BEEP NOT WORK, SCREENIMAGE NOT WORK, PRINT NOT WORK
8.         _PUTIMAGE , e, scr(a)
9.         _DELAY .1
10.         t## = TIMER
11.         ' _FREEIMAGE e&
12.  
13.         BEEP 'NOT WORK
14.     END IF
15.     a = a + 1
16. LOOP
17.  
18. SLEEP
19. FOR a = 0 TO 3
20.     SCREEN scr(a)
21.     SLEEP
22. NEXT a
23.  
24.  

I am sorry for alarm, i am IDIOT. Variable "a" is outside the loop...

[SMcNeill]

Is t# the timer, or t##?  Is this a typing goof, or deliberately two different variables?

[Petr]

Steve, i found it now.... i look to it but see it not...

[FellippeHeitor]

Maybe simplify it:

Code: QB64: [Select]

1. DIM scr(1 TO 3) AS LONG
2. FOR i = 1 TO 3
3.     PRINT i
4.     scr(i) = _SCREENIMAGE
5.     _DELAY 1
6. NEXT
7.  
8. FOR i = 1 TO 3
9.     PRINT "Press a key..."
10.     a$ = INPUT$(1)
11.     SCREEN scr(i)
12.     PRINT "Image #"; i
13. NEXT i
14.  

[FellippeHeitor]

Steve, i found it now.... i look to it but see it not...

BTW: OPTION _EXPLICIT at the top of your program would have saved you some debugging here.

[Petr]

Yes, there are 2 errors... Variable "a" muss be in IF...THEN condition and variable t is wrong, muss be double # type  on all places... thank you!

[TerryRitchie]

Steve, i found it now.... i look to it but see it not...

OPTION _EXPLICIT at the top of your program would have saved you some debugging here.

OPTION _EXPLICIT is the only way to go when dealing with code greater than 100 lines. It has saved me many hours of frustration.