Python Coding challenge - Day 587| What is the output of the following Python Code?

 

Code Explanation:

Function Decorator Definition

def add(f):

This defines a decorator function named add.

It accepts another function f as its argument.

The purpose is to modify or extend the behavior of f.

 Inner Wrapper Function

    def w(x): return f(x) + 10

Inside add, a new function w(x) is defined.

This wrapper function:

Calls f(x)

Then adds 10 to its result

So, it modifies the original function’s output.

Returning the Wrapper

    return w

The wrapper function w is returned.

So when add is used as a decorator, it replaces the original function with w.

Using the Decorator with @ Syntax

@add

def val(x): return x

The decorator @add is applied to the function val.

This is the same as:

def val(x): return x

val = add(val)

So, val(x) is now actually w(x), which returns x + 10.

Calling the Decorated Function

print(val(3))

val(3) is now w(3)

Inside w(3):

f(3) → original val(3) = 3

Then: 3 + 10 = 13

Final Output

13

The output of val(3) is 13, not just 3, because the decorator added 10 to it.

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