Functions allow code to be broken into reusable segments that perform well-defined single tasks. A function definition includes the function name, body, return value if any, and parameter list. Functions are declared using the def keyword followed by the function name and parameters in parentheses. To call a function, the function name and any parameters are written in parentheses. Functions must be defined before they are called.

1. FUNCTIONS

2. WHAT IS A FUNCTION?
 Functions
 Well Defined Single Tasks
 Creates easier to read code
 Segments an application to manage easier
 Creates reusable code segments
 Named using camelCase
 Provide proper names like variables
 The function name should specify what the function is intended to do.
 The list of instructions should accomplish what its name implies.

3. FUNCTION DEFINITION
Definition includes:
 name: name of the function. Function names follow
same rules as variables
 body: statements that perform
the function’s task
 return value: the value the function returns to the part of
the program that called it
 parameter list: variables containing
values passed to the function

4. DECLARING FUNCTION
Each function should perform only a single task
 Code:
 Declaring a Basic Function:
 def functionName ():
Function Body
 Common Errors: function names are case sensitive,
Trying to return a value with no return statement

5. CALLING A FUNCTION
 Functions just like variables need to be called in order
to be invoked
 Code:
 Calling a Function:
 functionName ()
o Ex.
main()
blink()

6. WRITE AND CALLING FUNCTIONS EXAMPLE