how to change a particular value in a line of a file based on a pattern

eg:

source file will be like
=================

99999999999 maximum number(0)
ksuisikjjsl;;l skjss''llsl
minimum number 0000000
maximum number of golds(0)


target should be like
=================

99999999999 maximum number(1)
ksuisikjjsl;;l skjss''llsl
minimum number 0000000
maximum number of golds(1)

the pattern i searched ihere is maximum, once i find the pattern the value which is (1) needs to change to (2).

i will give command line parameters for the pattern needs to be searched and the existing value and the value which it needs to be changed.

in the above example

Pattern to search is maximum
existing value is 1
value to be replaced is 2.

Note : the open and closed braces will be there in all the lines < (1) >.

1rst solution:
with vi:
edit the file with vi then
:%s/(1)/(2)

The requirement needs to be done in run time.

Note : I have a previous task after the completion of the task the script needs to be kicked off and the changes needs to be made in the file.

and also the reqt is < changing a particular value in a line of a file based on a pattern >

i would like to quickly clarify the reqt once again

eg:

source file will be like
=================

99999999999 maximum number(0)
ksuisikjjsl;;l skjss''llsl(0)
minimum number 0000000(0)
maximum number of golds(0)


target should be like
=================

99999999999 maximum number(1)
ksuisikjjsl;;l skjss''llsl(0)
minimum number 0000000(0)
maximum number of golds(1)

Well, that means do the same with sed...

Can you please guide me, with the same

Asume your file is called gigi
then:
cat gigi|while read line
do
OK=$(echo $line|grep maximum)
if [ "$OK" = "" ]
then
echo $line >>gigi.out
else
echo $OK | sed -e 's/(1)/(2)/'>>gigi.out
fi
done

#
then
mv gigi.out>gigi
I believe ther is no simple solution because you are looking for a pattern to do something else (modify the end of line...)