If you want to gain a better understanding of Symbian OS application development, one way is to study how other applications have been built. Whatsourcefiles is a tool that lists the source-code files used to build an emulator binary, for example, a .dll, .app or .exe file.

The tool can be found here>>

The tool requires Perl, which can be found here>>

The Whatsourcefiles tool understands binaries generated by the CodeWarrior compiler. It's invoked in the following manner:
 $ whatsourcefiles <binary file>

For example, when the tool is invoked for an application file, it may look like this:

$ whatsourcefiles helloworld.app
Reading helloworld.app...
\symbian\uiq_21\uiqexamples\helloworld\helloworld_application.cpp
\symbian\uiq_21\uiqexamples\helloworld\helloworld_appui.cpp
\symbian\uiq_21\uiqexamples\helloworld\helloworld_appview.cpp
\symbian\uiq_21\uiqexamples\helloworld\helloworld_document.cpp
\symbian\uiq_21\uiqexamples\helloworld\helloworld_main.cpp