UNIX SCRIPT : Read text file and write calculate sum

The following KSH script read the contents of a text file in CSV format , calculate its sum line by line and write the result to another file.  


#!/usr/bin/ksh

#PROGRAM BEGINS HERE

#DEFINING OUTPUT FILE
OUTPUTFILE=result.txt;

#CHECK FOR INPUT FILE
if [[ $# -eq 0 ]];then
        print "No Files";
        exit
fi;

#ACCEPTING INPUT FILE IF PRESENT
FILE=$1;

#READ FILE CONTENT LINE BY LINE
while read FILE
do
        VAR1=`echo $FILE| cut -d "," -f1`;
        VAR2=`echo $FILE|cut -d "," -f2`;
        SUM=`expr $VAR1 + $VAR2`;
        echo $SUM >> $OUTPUTFILE;
done < "$FILE"

#PROGRAM ENDS HERE