Templates for C programming language source (.c) and header (.h) files
Go to "Window -> Preferences -> C/C++ -> Code Style -> Code Templates -> Files -> C Source File" and click New. Write a name for the new template. In the Pattern section copy the contents of template.c file. Click apply. For the C Header File copy the template.h file in the Pattern section.
When you create a new file for a project, choose your own template.