I want creat a C program for Unix that can porcess the Regular Expression,like a simple Perl interpreter. Do I have to personally write an regexp engine?
http://www.gnu.org/software/libc/manual/html_node/Regular-Expressions.html
You might like to look for a library with it already coded. C uses librarys to allow you to include other peoples code into your work. I assume there are many regular expression librarys for you to use already to go!