Python Coding Challange - Question With Answer(01190225)

 

Step-by-Step Execution

1. Define outer() function

   • Inside outer(), a variable x is initialized with the value 2.
   • inner() is defined inside outer() and modifies x using nonlocal.

2. Define inner() function

   • inner() accesses the x variable from outer() using nonlocal.
   • The x *= 2 operation doubles the value of x.
   • inner() returns the updated value of x.

3. Return the inner() function

   • When outer() is called, it returns inner() instead of executing it immediately.

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Execution of closure = outer()

• outer() is executed, and inner() is returned.
• The x variable remains inside the closure and is remembered.

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First Call: print(closure())

• inner() is called.
• x = 2 (from outer()).
• x *= 2 → Now x = 4.
• Returns 4, so it prints 4.

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Second Call: print(closure())

• inner() is called again.
• x = 4 (previously modified value).
• x *= 2 → Now x = 8.
• Returns 8, so it prints 8.

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Final Output

4
8

Key Concepts Used

1. Closure: The function inner() remembers the variable x from outer(), even after outer() has finished execution.
2. nonlocal keyword: This allows inner() to modify x in outer(), instead of creating a new local variable.
3. State Retention: The value of x persists between function calls.