hi, everybody
I am s. kavin
today we gone a see functions.

Functions

Think of a function as a little helper in your code. It’s like a recipe that you can use over and over again.

Why do need functions

1.Reusability
2.Organization
3.Avoiding Repetition
4.Simplifying Complex Problems
eg:

def celsius_to_fahrenheit(celsius):
    return (celsius * 9/5) + 32

celsius1 = 25
fahrenheit1 = celsius_to_fahrenheit(celsius1)
print(f"{celsius1}°C is {fahrenheit1}°F")

celsius2 = 30
fahrenheit2 = celsius_to_fahrenheit(celsius2)
print(f"{celsius2}°C is {fahrenheit2}°F")

celsius3 = 15
fahrenheit3 = celsius_to_fahrenheit(celsius3)
print(f"{celsius3}°C is {fahrenheit3}°F")

Uses of functions

1. Greet People

def greet(name):
    print(f"Hello, {name}!")

greet("Alice")
greet("Bob")

2. Adding Two Numbers

def add(a, b):
    return a + b

result = add(5, 3)
print(f"The sum is: {result}")

3. Checking if a Number is Even or Odd

def is_even(number):
    return number % 2 == 0

print(is_even(4))  # True
print(is_even(7))  # False

04. Finding the maximum of Three numbers

def max_of_three(a, b, c):
    max = None
    if a > b:
        max = a
    else:
        max = b

    if max > c:
        return max
    else:
        return c

5. Calculating Factorial of a number

def factorial(n):
    if n == 0:
        return 1
    else:
        return n * factorial(n - 1)

print(factorial(5))  # 120

6. Calculating Area of a Circle

import math

def area_of_circle(radius):
    return math.pi * radius ** 2

print(area_of_circle(5))  # 78.53981633974483