Question

What will be the sequence of elements removed from the stack after performing the following operations?
Operations:
PUSH(10)
PUSH(20)
POP()
POP()
PUSH(30)
PUSH(40)
POP()
POP()
Options:
(A) 10
(B) 20
(C) 30
(D) 40
Choose the correct sequence from the options given below:

• A. (A), (B), (C), (D)
• B. (A), (B), (D), (C)
• C. (B), (A), (D), (C)
• D. (B), (A), (C), (D)

Answer 1

The Correct Option is C

The sequence of elements removed from the stack is 20, 10, 40, 30.

Additional Context:

• Stack Operations Breakdown:
  1. PUSH(10) → Stack: [10]
  2. PUSH(20) → Stack: [10, 20]
  3. POP() → Removes 20 (B) → Stack: [10]
  4. POP() → Removes 10 (A) → Stack: []
  5. PUSH(30) → Stack: [30]
  6. PUSH(40) → Stack: [30, 40]
  7. POP() → Removes 40 (D) → Stack: [30]
  8. POP() → Removes 30 (C) → Stack: []
• LIFO Principle:
  • Last element pushed is first popped
  • Visualized as vertical stack (like plates)
• Resulting Sequence:
  • First POP pair: 20, 10
  • Second POP pair: 40, 30

Correct Answer: (3) (B), (A), (D), (C).