Q3. What are functions? Explain Python function with parameters and return statements.

Definition of a Function in Python:

A function in Python is a reusable block of code that performs a specific task. It helps in breaking programs into smaller, manageable parts and enhances modularity and code reusability.

🔹 Types of Functions:

1. Built-in Functions – Functions provided by Python (e.g., print(), len(), input()).
2. User-defined Functions – Functions created by the programmer using the def keyword.

def function_name(parameters):
    return result

• def: Keyword used to define a function.
• function_name: Name of the function.
• parameters: Optional inputs.
• return: Optional statement to return a value.

Example: A Function with Parameters and Return Statement

def add_numbers(a, b):
    result = a + b
    return result

sum_value = add_numbers(5, 10)
print("Sum is:", sum_value)

Output: Sum is: 15

Explanation:

• a and b are parameters.
• add_numbers(5, 10) is a function call with arguments 5 and 10.
• The function returns a + b, which is stored in sum_value.

Return Statement:

• The return keyword is used to send the output back to the caller.
• Once return is executed, the function ends immediately.

Example: Using input(), int(), str() and return

def get_future_age():
age = int(input("What is your age? "))
return age + 1

next_age = get_future_age()
print("You will be " + str(next_age) + " in a year.")

Output (Assume user enters 19):

What is your age?
19
You will be 20 in a year.

Common Built-in Functions in Python:

Functions in Python allow you to structure code in a clean, logical, and efficient way. Using parameters and return values enhances code flexibility and reusability.