Dont know what is real requirement, but few things to know -
C is a language which is close to assembly but still a high level language. So in short most of the system development work is done in C and actually in initial days of C it was initially used for system development work, in particular the programs that make-up the operating system.
Example of C usage
Operating Systems
Language Compilers
Assemblers
Text Editors
Print Spoolers
Device Drivers
Databases
Language Interpreters
I/O Utilities
Now please be specific so that we can solve your problem -
