Python Coding challenge - Day 154 | What is the output of the following Python Code?

 

def outer():

    x = 10

    def inner():

        nonlocal x

        x += 5

        print("Inner:", x)

    inner()

    print("Outer:", x)

outer()

Solution and Explanation 

This code demonstrates nested functions in Python, along with the use of the nonlocal keyword.

Here's a breakdown of what each part does:

def outer():: This line defines a function named outer.

x = 10: Inside the outer function, a variable x is initialized with the value 10.

def inner():: Inside the outer function, another function named inner is defined.

nonlocal x: This statement inside the inner function tells Python that the variable x being referenced is not local to the inner function but belongs to the enclosing scope (which is the outer function in this case).

x += 5: Inside the inner function, x is incremented by 5.

print("Inner:", x): This line prints the value of x from the inner function after it has been incremented.

inner(): This line calls the inner function from within the outer function.

print("Outer:", x): After the inner function call, the value of x within the outer function is printed. Since x was modified within the inner function using the nonlocal keyword, its value will reflect the increment done inside the inner function.

outer(): Finally, the outer function is called, which executes the code inside it and its nested inner function.

When you run outer(), it will print:

Inner: 15

Outer: 15

This output shows that the inner function has successfully modified the value of x, and the change is reflected in the outer function as well.