Advanced Bash−Scripting Guide

let "row = $r" # Count center row of neighborhood.
IsValid $t_cen $row
# Valid cell position?
if [ $? −eq "$TRUE" ]
then
if [ ${array[$t_cen]} = "$ALIVE1" ] # Is it alive?
then
# Yes?
let "count += 1"
# Increment count.
fi
fi
let "row = $r − 1"
# Count top row.
IsValid $t_top $row
if [ $? −eq "$TRUE" ]
then
if [ ${array[$t_top]} = "$ALIVE1" ]
then
let "count += 1"
fi
fi
let "row = $r + 1"
# Count bottom row.
IsValid $t_bot $row
if [ $? −eq "$TRUE" ]
then
if [ ${array[$t_bot]} = "$ALIVE1" ]
then
let "count += 1"
fi
fi
done
Advanced Bash−Scripting Guide
if [ ${array[$cell_number]} = "$ALIVE1" ]
then
let "count −= 1" # Make sure value of tested cell itself
fi
#+ is not counted.
return $count
}
next_gen ()
{
# Update generation array.
local array
local i=0
array=( `echo "$1"` )
# Convert passed arg to array.
while [ "$i" −lt "$cells" ]
do
IsAlive "$1" $i ${array[$i]}
if [ $? −eq "$ALIVE" ]
then
array[$i]=.
else
array[$i]="_"
fi
let "i += 1"
done
# Is cell alive?
# If alive, then
#+ represent the cell as a period.
# Otherwise underscore
#+ (which will later be converted to space).
Appendix A. Contributed Scripts 383