# C Functions

A function is a piece of code that can be used repeatedly in a C program. A function is mainly of two types:

• Built in Functions; which are already defined in C Library.
• User Defined Functions; which are created and defined by users.

### Syntax:

Return_type functionName(parameters)

{

code to be executed;

}

Rules for using Functions:

• Void return type is used when nothing need to be returned from the function.
• Functions can also be used to return value. Return type such as int, long, char etc. are used to return a value from the function of the given type.
• A function starts with an opening curly brace ( { ) and ends with a closing curly brace ( } ).
• Arguments are the variables, inside the parentheses, after the function name which is used to pass informations to functions.
• For multiple arguments, comma should be used for separation.
• Default argument value can also be specified in a function. If no argument is specified, the function will take the default argument.

Calling a Function in C:

In order to get the value returned from the function, the function need to be called in the program.

### Syntax:

Variable_name = function_name (parameters_values);

Example:

#include<stdio.h> int writeMsg() { printf ("My First Program using Function!"); return 0; }   void main() { writeMsg(); }

Output

My First Program using Function!