Array Assignment Problem

paulmoreland · 2021-01-20 16:32

I feel very close now and would really appreciate some help getting over the finishing line.

A sequence of 125 is made up of a number of cycles with varying numbers of active elements (between 1 and 5 per cycle )

The sticking point for me is:

 IF flag = 2 THEN
     confirmed(i)=active
ENDIF

If I run the code with the array assignment commented out the debug output looks perfect, as soon as I uncomment the line below it all goes horribly wrong.

confirmed(i)=active

' {$STAMP BS2sx}
' {$PBASIC 2.5}

'---------------variables---------------
sequence VAR Byte
relays VAR Byte
irelays VAR Byte
cycles VAR Byte
active VAR Nib
i VAR Nib
x VAR Nib
confirmed VAR Byte(10)
flag VAR Nib
'---------------initialise---------------
sequence=0
relays=0
irelays=0
cycles=0
active=0
i=0
x=0
flag=0

main:
  ' sets up outer loop to count 125 cycles
  DO WHILE (sequence < 125)
    ' generate random number between 1-5 relays to fire
    cycles=(relays // 5+1)
    RANDOM relays
    ' check if this cycle would sequence over 125. If it would  decrement sequence otherwise increment sequence
    IF sequence + cycles > 125 THEN
        sequence = sequence - cycles
    ELSE
        sequence = sequence + cycles
        'setup loop to call getActive subroutine
        DEBUG DEC ? cycles, CR
        FOR i = 1 TO cycles
          GOSUB getActive
          'tests the value of flag after getActive and if flag = 2 current active can be added to the array.
          IF flag = 2 THEN
               'confirmed(i)=active
               DEBUG "confirmed("
               DEBUG DEC i
               DEBUG ") = "
               DEBUG DEC active, CR
          ENDIF
        NEXT
        DEBUG "--------------------",CR
    ENDIF
  LOOP
  HIGH 15
  DEBUG CR
  DEBUG "End of sequence"
  PAUSE 2000
  LOW 15
  END

getActive:
  'generate random number between 1-5 which is active
  flag=0
  x=0
  active=(irelays // 5+1)
  RANDOM irelays
  'need to run through array and set flag to 1 if active already in array or 2 if not and can be added to the array.
  DO WHILE (flag <> 2)
    FOR x = 1 TO 5
      IF active = confirmed(x) THEN
        flag = 1
      ELSE
        IF flag <> 1 THEN
          flag = 2
        ENDIF
      ENDIF
    NEXT
  LOOP
  RETURN

Also I've just spotted another issue. getActive:is supposed to generate a new "active" then loop through the confirmed array looking to see if it already exists in it. If it does it sets flag=1. All my testing shows this to work and only returns 2 if the array doesn't already hold that particular value.

Back in the main:

IF flag = 2 THEN
               'confirmed(i)=active
               DEBUG "confirmed("
               DEBUG DEC i
               DEBUG ") = "
               DEBUG DEC active, CR
          ENDIF

is supposed to check the value of flag and if it's 2 write the active into the current index(i) so duplicates shouldn't be possible. As the assigning to the array is broken (see above) in debug I just concatenate the values to see what the assignment statement would look like, when I look at this i do see duplicates. What's the problem there?

JaanDoh · 2021-01-24 05:09

Hi Paul,

I've never really used the stamp before, but one basic is usually similar to another.

And hence...

I can see a few little errors and have pasted the (what I think is the) corrected code below,
but it wouldn't do any harm to get a further opinions.

I've added comments to explain each step of the changes.
hope it helps...

The main points were the MOD statement, where

cycles=(relays // 5) + 1

This is relays MOD 5

is not the same as

cycles=(relays // 5+1)

which is relays MOD 6

and also the order in which you generated your random number,
I think you had the two lines back to front, but since I don't know stamp very well I cant be sure.

' {$STAMP BS2sx}
' {$PBASIC 2.5}


'---------------variables---------------
sequence VAR Byte
relays VAR Byte
irelays VAR Byte
cycles VAR Byte
active VAR Byte
i VAR Byte
x VAR Byte
' reduced array size to 5 since you only have 5 relays
confirmed VAR Byte(5)	
flag VAR Nib


'---------------initialise---------------
sequence=0
relays=0
irelays=0
cycles=0
active=0
i=0
x=0
flag=0




main:
  ' seed relays with number between 0  and65535
  relays = 123			

  ' sets up outer loop to count 125 cycles
  DO WHILE (sequence < 125)

    ' generate random number 
    RANDOM relays		
    
    ' mod random number with 5 to end up with a value between 1 + 5
    cycles=(relays // 5) + 1	

    ' check if this cycle would sequence over 125. If it would  decrement sequence otherwise increment sequence
    IF sequence + cycles > 125 THEN
        sequence = sequence - cycles
    ELSE
        sequence = sequence + cycles

        'setup loop to call getActive subroutine
        DEBUG DEC ? cycles, CR

        FOR i = 1 TO cycles
          GOSUB getActive
          'tests the value of flag after getActive and if flag = 2 current active can be added to the array.
          IF flag = 2 THEN
               confirmed(i-1)=active
               DEBUG "confirmed("
               DEBUG DEC i
               DEBUG ") = "
               DEBUG DEC active, CR
          ENDIF
        NEXT
        DEBUG "--------------------",CR
    ENDIF
  LOOP
  HIGH 15
  DEBUG CR
  DEBUG "End of sequence"
  PAUSE 2000
  LOW 15
  END


getActive:
  ' generate random number between 1-5 which is active
  flag=0
  x=0

  ' seed irelays with number between 0 and 65535
  irelays=relays

  ' get random number between 0 and 65535
  RANDOM irelays

  ' mod random number with 5 to end up with a value between 1 + 5
  active=(irelays // 5) + 1

  'need to run through array and set flag to 1 if active already in array or 2 if not and can be added to the array.
  FOR x = 1 TO 5
    IF active = confirmed(x) THEN
      flag = 1
      exit ' exit for loop we matched the nummber so theres no need to continue looping?
    ELSE
      flag = 2
    ENDIF
  NEXT
  RETURN

Array Assignment Problem

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