How to compile and execute lex,yac,c and java programs

Is the problem that you don't know how to compile and execute these programs on a Mac, or just that you don't know how to compile and execute them?

Mac OS X is really just a version of BSD Unix, as far as programs like like bison, flex and gcc are concerned...and even when Apple specific versions are provided in the Developer Tools, there are symlinks in the usual places in the Unix file hierarchy.

For problems with lex and yacc, I suggest you start with their own references, for example, here.

Or you could just use %option noyywrap, if you only have one file to scan.

Or you could link to libfl.a using -lfl and use the default version from that library.

But you really should (as Keith Barkley was subtly hinting at) learn how these tools work and why they work that way.

Since yylex is something you supply, does it call yywrap?

Do a google search for yywrap and you will see that it is something you are supposed to supply. (There is an option that suppresses it, too.)