Doubt??? [scope of variables]

Shell Programming and Scripting
1

Heres an example.....

[qzv2jm] <~/abc>$ cat textfile
line 1
line 2
line 3
line 4
line 5

[qzv2jm] <~/abc>$ cat try.sh
#/bin/ksh
for runs in 1 2 3
do
A=$runs
echo "Inside A : $A"
done

echo "Outside A : $A" <- works fine

cat textfile | while read var
do
echo $var
x=$var+1
echo "inside x = $x"
done
echo "outside x = $x" <- Does not work

[qzv2jm] <~/abc>$ try.sh
Inside A : 1
Inside A : 2
Inside A : 3
Outside A : 3 <---worked
line 1
inside x = line 1+1
line 2
inside x = line 2+1
line 3
inside x = line 3+1
line 4
inside x = line 4+1
line 5
inside x = line 5+1
outside x = <----doubt??
[qzv2jm] <~/abc>$

Question: How can I make 'x' global so that I get the value outside the loop:confused:.

2 
% unset x
% cat file
line 1
line 2
line 3
line 4
line 5
% while read;do x="$x $REPLY";done<file
% echo "$x"
 line 1 line 2 line 3 line 4 line 5