I am sorry that i couldnot help your out earlier.Considering the fact that your time is valuable I thought that other experts here would help,but as no body responded,here i am back again.
(MAybe the weekends hangover is till there
This was a nice interesting program.Here's your download link for the program :-
The Delete link:-
I hope you know how to handle files but its my duty to explain the steps incase you face any problems.
Create a text file using notepad or wordpad.Let the name of the text file beCustomertxt
Write something into the text file.using lowercase letters,uppercase letters and symbols.Close the text file
Save the text file to the same location where you are saving you c file.
run the c program.
It will ask you file name.Enter file name asCustomertxt
The program will run and do its job.
Close the program and open the text file with a text editor like notepad.
You will see that as the program intended all the lowercase letters will be converted into the uppercase letters excluding the special characters.
Interesting .Isn't it?
Let me know if you have any further doubts,