Android Question After loop ends, variable keeps counting?

[ilan]

hi

i am a little bit confused.

i have bugs in my app and i try to debug it and found something strange.

    For y = 0 To 2
        For x = 0 To 2
            'do nothing
        Next
        Log(x)
    Next

so x runs from 0 to 2
i was thinking that x should be logged 2 because this is the last value that was set to x but the logs gives me 3

why is that?

*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create (first time) **
3
3
3
Call B4XPages.GetManager.LogEvents = True to enable logging B4XPages events.
** Activity (main) Resume **
** Activity (main) Pause event (activity is not paused). **

is there a reason why x keeps counting even if i set it to stop at the value 2?

thanks

 

[udg]

I would say that it's expected.
You set a loop with values 0-2. Then Next is executed, the counting var is incremented, the loop "finds" it's greater than your upper limit and so exits the loop. Log shows this final values (i.e 3).

 

[tchart]

0,1,2 = 3 iterations

 

[DonManfred]

why is that?

I guess NEXT will add 1 to the value.
THEN it returns to the for line which then ignore the new value because the requirement do not match. Means you are leaving the loop at the for-line then; not at NEXT...

    For y = 0 To 2
        For x = 0 To 2
            'do nothing
            Log(x)
        Next
    Next

will log what you expected...

 

[ilan]

what happens if you count using step?
In my opinion x is last set to 2 so i should get 2 inside the event even if i call it after loop ends

 

[teddybear]

what happens if you count using step?
In my opinion x is last set to 2 so i should get 2 inside the event even if i call it after loop ends

It's no different with not using step.
if you want to x to be 2 after the loop ends, you may use for each iteration of a list instead of for to.

    For Each x As Int In Array As Int (0,1,2)
        Log(x)
    Next
    Log(x)

 

[AnandGupta]

This is programming logic for FOR-NEXT
It is similar to WHILE-LOOP as below,

x = 0
do while x <= 2
    'do nothing
    x = x+1
loop
Log(x)