Multiple Choice Questions on Stack
1. 1. What is a stack in data structures?
A) A FIFO (First In First Out) structure
B) A LIFO (Last In First Out) structure
C) A FILO (First In Last Out) structure
D) Both B and C
Answer: D) Both B and C
2. 2. Which of the following operations is not performed on a stack?
A) Push
B) Pop
C) Peek
D) Enqueue
Answer: D) Enqueue
3. 3. What is the time complexity of the push and pop operations in a stack (assuming no resizing)?
A) O(1)
B) O(n)
C) O(log n)
D) O(n²)
Answer: A) O(1)
4. 4. What happens when you pop from an empty stack?
A) Underflow
B) Overflow
C) The stack resets
D) A new stack is created
Answer: A) Underflow
5. 5. What is the result of the following sequence of operations? Push(10), Push(20), Pop(),
Push(30), Peek()
A) 10
B) 20
C) 30
D) Stack is empty
Answer: C) 30
6. 6. What data structure can be used to convert infix expressions to postfix expressions?
A) Queue
B) Stack
C) Tree
D) Linked List
Answer: B) Stack
7. 7. Which data structure is used in function call recursion?
A) Queue
B) Stack
C) Heap
D) Linked List
Answer: B) Stack
8. 8. What does the 'peek' operation do in a stack?
A) Removes the top element
B) Returns the top element without removing it
C) Checks if the stack is empty
D) Returns the bottom element
Answer: B) Returns the top element without removing it
9. 9. What is the maximum number of elements that can be stored in a stack of size n?
A) n-1
B) n
C) n+1
D) 2n
Answer: B) n
10. 10. Which condition indicates that a stack is full?
A) Top == -1
B) Top == size - 1
C) Top == size + 1
D) Top == 0
Answer: B) Top == size - 1
11. 11. In which case does a stack overflow occur?
A) When too many elements are popped
B) When a stack is empty
C) When more elements are pushed than its size
D) When accessing an element out of range
Answer: C) When more elements are pushed than its size
12. 12. A stack can be implemented using which data structure?
A) Array
B) Linked List
C) Both A and B
D) None of the above
Answer: C) Both A and B
13. 13. Which type of memory is typically used for implementing stacks in function calls?
A) Heap
B) Stack memory
C) Queue
D) Registers
Answer: B) Stack memory
14. 14. Which of the following applications use stacks?
A) Undo/Redo feature in text editors
B) Expression evaluation
C) Backtracking (Maze solving, Sudoku, etc.)
D) All of the above
Answer: D) All of the above
15. 15. What is the main advantage of using a linked list to implement a stack instead of an array?
A) Dynamic size adjustment
B) Faster operations
C) Requires less memory
D) Simple implementation
Answer: A) Dynamic size adjustment
16. 16. Which of the following is not an application of a stack?
A) Reversing a string
B) Managing function calls
C) Implementing a queue
D) Depth-first search (DFS)
Answer: C) Implementing a queue
17. 17. What is the postfix expression for the infix expression (A + B) * C?
A) AB + C *
B) A B + C *
C) A B C * +
D) A + B * C
Answer: B) A B + C *
18. 18. In the implementation of a stack using an array, where is the top of the stack initialized?
A) 0
B) 1
C) -1
D) Size of the array
Answer: C) -1
19. 19. What is the main drawback of implementing a stack using an array?
A) Stack overflow can occur if the array is full
B) Stack underflow can occur if the stack is empty
C) Both A and B
D) None of the above
Answer: C) Both A and B
20. 20. What is the advantage of a circular stack over a linear stack?
A) More efficient memory utilization
B) Faster access times
C) Easier implementation
D) More memory required
Answer: A) More efficient memory utilization
