The main task of the programmer is to develop algorithms and computer programs. Of course, options and types of programs has a great variety and to better explain what they do programmers, here are three of the main specializations:
Application programmers - creating software for various tasks (editors, games, accounting software, CRM-system, etc.).
Web programmers (often a PHP programmers) - Internet Services - create a website for the system management program sites or online stores, etc.
System programmers - developing operating systems and shells for the database, as well as solve other similar problems.