Q.What does the return statement do in a function ? Explain with the help of an example.

Concept: The return statement exits a function and sends a value back to the caller. Without it, a function returns None by default.

The key idea is that return does two things: it stops the function immediately, and it passes a result to the line that called the function. If you just want to stop without sending a value, you can write return alone (which returns None).

Example:

def square(x):
    result = x * x
    return result

y = square(5)   # y gets the value 25
print(y)        # prints 25
``` …

The Core Idea

Think of a function like a vending machine. You put in money (arguments), press a button (call the function), and the machine gives you a product (the return value). The return statement is the mechanism that actually hands you that product. Without it, the machine might do work inside — lights flash, gears turn — but nothing comes out for you to hold.

In programming, when you call a function, you usually want it to compute something and give you the result. The return statement does two things at once:

1. It sends a value back to the place where the function was called.
2. It immediately stops the function — no further code in the function runs after return.

If a function has no return statement, Python still returns something: the special value None. This is like the vending machine saying "here's nothing" — technically a response, but not useful.

Step-by-Step Explanation

1. What return does in a function

   When Python encounters return inside a function, it evaluates the expression after return (if any), then hands that value back to the caller. The function's execution ends right there — any lines after return are ignored.

2. The default return value

   If a function ends without hitting a return statement, Python automatically returns None. This is a common source of bugs for beginners: they write a function that prints a result but forget to return it, then wonder why the variable they assigned gets None.

3. Example: A function that returns a value

   Consider a function that calculates the area of a rectangle:

   def rectangle_area(length, breadth):
       area = length * breadth
       return area
   

   When you call result = rectangle_area(5, 3), the function computes 15, and return sends that 15 back. Now result holds 15. You can use it in further calculations.

4. Example: A function without return

   Compare with this version:

   def rectangle_area(length, breadth):
       area = length * breadth
       print(area)
   

   Calling result = rectangle_area(5, 3) prints 15 to the screen, but result becomes None. The function did the work but didn't hand back the value — it only showed it. …