masking

Special_K

dose any one have a chart or a link on how to mask a random number to a number range?
like this

  drive = randnum & %1111           'mask off  number between 0-15 

I need to mask one variable to numbers between 0 and 7 and one from 0 to 14.
should I use the max command?

randnum  =  drive MAX 7

any ideas?

Post Edited (Special_K) : 11/11/2006 4:51:44 AM GMT

Chris Savage

Hello,
·
·· The following thread has code for generating random numbers in a range.· The trick is in using the modulus operator.· Take care.

http://forums.parallax.com/showthread.php?p=522895

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support

Special_K

i AM USING THIS CODE

drive = randnum // DDIR     'ddir = 7
  DEBUG "drive",BIN drive,CR
  DEBUG "drive  TIME",BIN dTIME,CR
  BRANCH drive, [noparse][[/noparse]FORward, rightturn1, FORward, backward, forward, leftturn1, halt, FORward ]
  tdone:
  RETURN

but I am getting numbers way out of range
drive can equal 100

Mike Green

BIN drive
This displays the value of drive as a binary number. "100" in binary is the value four which is a correct value for what you're trying to do.

TechnoRobbo

I addition to Mr. Green's advice let me point out that you have 8 BRANCH choices you'll never get to the eight one with your code:

·········· drive·=·randnum·//·DDIR······'ddir·=·7

Modulus is the remainder of a division therefore the remainder of a division by 7 is 0 to 6 inclusive.

Try setting DDIR to 8 your results will be 0 to 7 inclusive and thats what the ·"BRANCH" instructions looking for.

Of course your code uses the "Forward" label 4 times so it won't matter too much in this example, but if you reuse your code elsewhere or decide to trim down you BRANCH statement it will give you problems.
·

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Have Fun


TR

Post Edited (TechnoRobbo) : 11/15/2006 11:33:28 AM GMT

Special_K

thanks,
I found the BIN thing last night and changed it forgot to update.
I will change the ddir to equal 8.
The branch code has forward 4 times to stack the deck because I want the random motion to be more forward rather then in circles.