Basically structure of the C program is divided into six different sections,
1. Documentation section: The Documentation section consists of a set of comment lines.
2. Link section: The link section provides instruction to the compiler to link the header files or functions from the system library.
3. Definition section: The definition section defines all symbolic constants such by using the #define directive.
4. Global declaration section: There are some variables that are used in more than one function, such variables are called global variables.
In C there are two types of variable declaration,
Local variable declaration: Variables that are declared inside the main function.
Global variable declaration: Variables that are declared outside the main function.
5. Main function section: Every C-program should have one main() function.
This section contains two parts:
Declaration part
Executable part
6. Sub-program section: If the program is a multi-function program, then the subprogram section contains all user-defined functions that are called in the main() function.