Lesson 10 – Functions

There are two types of functions that we can use in the C language. 

  • Library functions
  • User-defined functions

Library functions can be used by including the respective header file and then calling the function in the main body.

User-defined functions are the ones defined by the users as per their requirements.

Defining these is done in three steps:

  1. Declaring the function before “main”

  For example, message();

  Here “message” is the name of the function. Note that we have used statement terminator (;) here.

  1. Calling the function in the main.

For example,

 main()

  {

  message();

  }

Again here we need to use statement terminator.

  1. Defining the function after “main”

  For example, 

message(); —> 1

main()

{

message(); —> 2

}

message() —> 3 

{

Printf (“Hello functions!!!”);

}

able on which decision will depend.