BASIC stamp manual v2.2

GOSUB – BASIC Stamp Command Reference
Page 212 • BASIC Stamp Syntax and Reference Manual 2.2 • www.parallax.com
Demo Program (GOSUB.bs2)
' GOSUB.bs2
' This program is a guessing game that generates a random number in a
' subroutine called Pick_A_Number. It is written to stop after ten
' guesses. To see a common bug associated with GOSUB, delete or comment
' out the line beginning with END after the FOR-NEXT loop. This means
' that after the loop is finished, the program will wander into the
' Pick_A_Number subroutine. When the RETURN at the end executes, the
' program will go back to the beginning of the program. This will cause
' the program to execute endlessly. Make sure that your programs can't
' accidentally execute subroutines!
' {$STAMP BS2}
' {$PBASIC 2.5}
rounds VAR Byte ' number of reps
numGen VAR Word ' random number holder
myNum VAR Byte ' random number, 1-10
Setup:
numGen = 11500 ' initialize random "seed"
Main:
FOR rounds = 1 TO 10
DEBUG CLS, "Pick a number from 1 to 10", CR
GOSUB Pick_A_Number
PAUSE 2000 ' dramatic pause
DEBUG "My number was: ", DEC myNum ' show the number
PAUSE 1000 ' another pause.
NEXT
DEBUG CLS, "Done"
END ' end program
' Random-number subroutine. A subroutine is just a piece of code with
' the RETURN instruction at the end. Always make sure your program enters
' subroutines with a GOSUB. If you don't, the RETURN won't have the
' correct address, and your program will have a bug!
Pick_A_Number:
RANDOM numGen ' stir up the bits of NumGen.
DEBUG DEC ? numGen
myNum = numGen / 6550 MIN 1 ' scale to fit 1-10 range.
RETURN ' go back to 1st instruction
' after GOSUB that got us here
All 2
NOTE: This example program can be
used with all BS2 models by changing
the $STAMP directive accordingly.