exec command

hai
i want know the difference between two shell scripts those are

1)
a=2004
echo $a #output------2004
exec < inputfile
while read line
do
echo $a #output-------2004
a=2005
echo $line
echo $a #output -------2005
done
echo $a #output------2005

2)
a=2004
echo $a #output------ 2004
while read line
do
echo $a #output------2004
a=2005
echo $line
echo $a #output-----2005
done < inputfile
echo $a #output------2004

I am produceing output in coresponding row please observe it and tell me why the difference is????????

mailny Observe the difference between last line echo $a output

Sounds like another class assignment - if you can't figure it out on your own, please request help from your instructor.

Closing thread.