FUNCTIONS:
==========

DIGITAL CALCULATOR
	ARITHMETIC OPERATIONS
	=======================
	TIGONOMETRIC OPERATIONS
	=======================
	INTEGRATIONS
	============
	DIFFERENTIATIONS
	=================
	LOGERTHIMS
	=============
	ETC.

running the application
we may have errors
	tracing of the error
		from the complex code is really difficult.
	we should clear that error.

to make identify and simplify the error easily, we need a concept called functions.
for easy debugging ==> functions are need.

what if a function?
===================
named block, which we can use to define the functionality to perform.
==> functions can use in real-time like:
	1) function definition
	2) function call/function invoke

function definition:
====================
	that:
		1) name of the function
		2) about parameters
			length of parameters

function can accept the data in terms of parameters/arguments

Note:
=====
function definition is always at the top of the program.

Syntax:
	def function-name(parameter1, parameter2, parameter3,...):
		instruction-1
		instruction-2
Note:
=====
if the function without parameters,
	def function-name():
		instructions

function call/function invoke:
==============================
note:
====
the function call is always after the function definition.

==> to invoke the function definition (to make perform through the function), we need the function call.

Syntax:
	function-name(value1, value2, value3,...)

if the function with '0' parameters:
	function-name()

Note:
=====
We can allow to give any number of function calls within the program.

Note:
=====
1) we can write any number of function definitions within the program.
2) functions can be with or without parameters
3) functions can define the operation:
	by taking the data/values through the function call.
4) functions can do:
	i) take arguments
	ii) process the arguments
	iii) can give the results.

# function definition & function call

# function definition

def greets():
    print("Hello")
    print("Good Morning.")

def ariths(para1,para2):
    addition = para1 + para2
    subtraction = para1 - para2
    multiplication = para1 * para2

    print("The Results are:")
    print(addition)
    print(subtraction)
    print(multiplication)


# function call

# greets()
# greets()
# greets()

for i in range(5):
    greets()

ariths(10,20)

===============================================

The functions are two types:
	1) Inbuilt Functions/Pre-defined functions
		ex: len(), print(), input(), sort(), sorted() etc.

	2) User-Defined Functions
		according to the application requirement, the programmer can add the functionality.

======================================

Note:
=====
Functions can return a value.
Syntax:
	return value-name

# function definition & function call

# function definition

def greets():
    print("Hello")
    print("Good Morning.")

def ariths(para1,para2):
    addition = para1 + para2
    subtraction = para1 - para2
    multiplication = para1 * para2

    # print("The Results are:")
    # print(addition)
    # print(subtraction)
    # print(multiplication)
    return addition, subtraction, multiplication


# function call

# greets()
# greets()
# greets()

for i in range(5):
    greets()

# print(greets())

# result = ariths(10,20)
# print("Sum = ",result)

# print("The Sum = ",ariths(10,20))

res1,res2,res3 = ariths(10,20)

print("Sum = ", res1)
print("Minus = ",res2)
print("Product = ",res3)

print("The Results = ",ariths(10,20))

===============================================

Types of User-defined functions:
================================
four types:
	1) functions without parameters and without returning values
	Syntax:
		def function-name():
			implementation

# function without parameters and no return values

def Circle():
    radius = int(input("Enter a radius:"))

    PI = 3.1417

    area_circle = PI * radius * radius

    print("The Area of the circle = ",area_circle)

Circle()

	2) functions without parameters and with returning values
	Syntax:
		def function-name():
			implementation
			
			return value/value-name

def findBigger():
    a = int(input("Enter a value for a:"))
    b = int(input("Enter a value for b:"))
    c = int(input("Enter a value for c:"))

    if a > b and a > c:
        bigger = a
        # return bigger

    elif b > c:
        bigger = b
        # return bigger

    else:
        bigger = c
        # return bigger

    return bigger

biggest = findBigger()

print("The Biggest number among three integers = ",biggest)

	3) functions with parameters and no returning values
	Syntax:
		def function-name(p1, p2, p3,...):
			implementation

# function with parameters and no return value

def Triangle(a,b,c):
    s = (a + b + c)/2

    area = (s * (s-a) * (s-b) * (s-c)) ** 0.5

    print("The Area of the Triangle = ",area)

Triangle(7,8,9)

	4) functions with parameters and with returning values
	Syntax:
		def function-name(p1, p2, p3,...):
			implementation
			return values/value-names
ex: return a, b, c

def Triangle(a,b,c):
    if a == b and a == c and b == c:
        type = "An Equilateral Triangle."

    elif a == b or a == c or b == c:
        type = "An Isosceles Triangle."

    else:
        type = "A Scalene Triangle."

    return type

print("The Type of the Triangle = ",Triangle(7,8,9))