# Stack Operations

This set of Data Structure Multiple Choice Questions & Answers (MCQs) focuses on “Stack Operations – 1”.

1. Process of inserting an element in stack is called ____________
a) Create
b) Push
c) Evaluation
d) Pop

2. Process of removing an element from stack is called __________
a) Create
b) Push
c) Evaluation
d) Pop

3. In a stack, if a user tries to remove an element from an empty stack it is called _________
a) Underflow
b) Empty collection
c) Overflow
d) Garbage Collection

4. Pushing an element into stack already having five elements and stack size of 5, then stack becomes ___________
a) Overflow
b) Crash
c) Underflow
d) User flow

5. Entries in a stack are “ordered”. What is the meaning of this statement?
a) A collection of stacks is sortable
b) Stack entries may be compared with the ‘<‘ operation
c) The entries are stored in a linked list
d) There is a Sequential entry that is one by one

6. Which of the following is not the application of stack?
a) A parentheses balancing program
b) Tracking of local variables at run time
c) Compiler Syntax Analyzer
d) Data Transfer between two asynchronous process

7. Consider the usual algorithm for determining whether a sequence of parentheses is balanced. The maximum number of parentheses that appear on the stack AT ANY ONE TIME when the algorithm analyzes: (()(())(()))?
a) 1
b) 2
c) 3
d) 4 or more

8. Consider the usual algorithm for determining whether a sequence of parentheses is balanced. Suppose that you run the algorithm on a sequence that contains 2 left parentheses and 3 right parentheses (in some order). The maximum number of parentheses that appear on the stack AT ANY ONE TIME during the computation?
a) 1
b) 2
c) 3
d) 4 or more

9. What is the value of the postfix expression 6 3 2 4 + – *?
a) 1
b) 40
c) 74
d) -18

10. Here is an infix expression: 4 + 3*(6*3-12). Suppose that we are using the usual stack algorithm to convert the expression from infix to postfix notation. The maximum number of symbols that will appear on the stack AT ONE TIME during the conversion of this expression?
a) 1
b) 2
c) 3
d) 4

11. The result of evaluating the postfix expression 5, 4, 6, +, *, 4, 9, 3, /, +, * is?
a) 600
b) 350
c) 650
d) 588

12. Convert the following infix expressions into its equivalent postfix expressions.
(A + B ⋀D)/(E – F)+G
a) (A B D ⋀ + E F – / G +)
b) (A B D +⋀ E F – / G +)
c) (A B D ⋀ + E F/- G +)
d) (A B D E F + ⋀ / – G +)

13. Convert the following Infix expression to Postfix form using a stack.
x + y * z + (p * q + r) * s, Follow usual precedence rule and assume that the expression is legal.
a) xyz*+pq*r+s*+
b) xyz*+pq*r+s+*
c) xyz+*pq*r+s*+
d) xyzp+**qr+s*+

14. Which of the following statement(s) about stack data structure is/are NOT correct?
a) Linked List are used for implementing Stacks
b) Top of the Stack always contain the new node
c) Stack is the FIFO data structure
d) Null link is present in the last node at the bottom of the stack

15. Consider the following operation performed on a stack of size 5.

``````Push(1);
Pop();
Push(2);
Push(3);
Pop();
Push(4);
Pop();
Pop();
Push(5);``````

After the completion of all operation, the number of elements present in stack is?
a) 1
b) 2
c) 3
d) 4

16. Which of the following is not an inherent application of stack?
a) Reversing a string
b) Evaluation of postfix expression
c) Implementation of recursion
d) Job scheduling

17. The type of expression in which operator succeeds its operands is?
a) Infix Expression
b) Prefix Expression
c) Postfix Expression
d) Both Prefix and Postfix Expressions

18. Assume that the operators +,-, X are left associative and ^ is right associative. The order of precedence (from highest to lowest) is ^, X, +, -. The postfix expression for the infix expression a + b X c – d ^ e ^ f is?
a) abc X+ def ^^ –
b) abc X+ de^f^ –
c) ab+c Xd – e ^f^
d) -+aXbc^ ^def

19. If the elements “A”, “B”, “C” and “D” are placed in a stack and are deleted one at a time, what is the order of removal?
a) ABCD
b) DCBA
c) DCAB
d) ABDC

20. The postfix form of the expression (A+ B)*(C*D- E)*F / G is?
a) AB+ CD*E – FG /**
b) AB + CD* E – F **G /
c) AB + CD* E – *F *G /
d) AB + CDE * – * F *G /

21. The data structure required to check whether an expression contains a balanced parenthesis is?
a) Stack
b) Queue
c) Array
d) Tree

22. What data structure would you mostly likely see in non recursive implementation of a recursive algorithm?
b) Stack
c) Queue
d) Tree

23. The process of accessing data stored in a serial access memory is similar to manipulating data on a ________
a) Heap
b) Binary Tree
c) Array
d) Stack

24. The postfix form of A*B+C/D is?
a) *AB/CD+
b) AB*CD/+
c) A*BC+/D
d) ABCD+/*

25. Which data structure is needed to convert infix notation to postfix notation?
a) Branch
b) Tree
c) Queue
d) Stack

26. The prefix form of A-B/ (C * D ^ E) is?
a) -/*^ACBDE
b) -ABCD*^DE
c) -A/B*C^DE
d) -A/BC*^DE

27. What is the result of the following operation?
Top (Push (S, X))
a) X
b) X+S
c) S
d) XS

28. The prefix form of an infix expression (p + q) – (r * t) is?
a) + pq – *rt
b) – +pqr * t
c) – +pq * rt
d) – + * pqrt

29. Which data structure is used for implementing recursion?
a) Queue
b) Stack
c) Array
d) List