Python Coding challenge - Day 687| What is the output of the following Python Code?

 

Code Explanation:

1. Defining the decorator function

def constant(f):

A decorator named constant is defined.

It takes a function f as its input.

The purpose is to replace the normal behavior of f.

2. Defining the wrapper inside the decorator

    def wrap(*args, **kwargs):

        return 42

Inside constant, a function wrap is defined.

wrap accepts any number of arguments (*args for positional, **kwargs for keyword).

Instead of using those arguments or calling the original function, it always returns 42.

3. Returning the wrapper

    return wrap

The decorator does not return the original function f.

Instead, it returns the new wrap function.

This means: whenever you call the decorated function, you’ll actually be calling wrap.

4. Decorating the add function

@constant

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

The @constant decorator is applied to add.

Equivalent to writing:

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

add = constant(add)

After decoration, add is no longer the original function.

It is now wrap (the inner function returned by constant).

5. Calling the decorated function

print(add(5, 10))

You might expect add(5, 10) → 5 + 10 = 15.

BUT since add has been replaced by wrap, the call is:

wrap(5, 10)

Inside wrap, the arguments (5, 10) are completely ignored.

It just returns 42.

Final Output

42

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