Understanding data structures is very important. Data structures help in organizing and storing data efficiently so that it can be accessed and used easily.
In this post, we have provided a collection of Data Structure MCQ questions with answers that are useful for students, beginners, and exam preparation. These questions cover important topics like arrays, stacks, queues, and basic concepts of data structures.
Data Structure MCQ
1. What is a data structure?
a. A programming language
b. An operating system
c. A way to store and organise data
d. None of the above
2. Which of the following is known as a linear data structure?
a. Binary Tree
b. Graph
c. Hash Table
d. Array
3. Examples of data structures are __.
a. Array
b. List
c. Binary Tree
d. All of the above
4. Finding the location of a record with a given key value is known as __.
a. Searching
b. Traversing
c. Sorting
d. None of the above
5. The maximum number of nodes of a symmetric binary tree with a depth of 7 is __.
a. 125
b. 127
c. 128
d. None of the above
6. The data in the data structure are processed by certain operations like _.
a. Traversing
b. Shorting
c. Searching
d. All of the above
7. Which of the following operations is used for processing certain items in a record, and each record is accessed exactly once?
a. Traversing
b. Searching
c. Inserting
d. Sorting
8. Which of the following operations is used for arranging the records in some order?
a. Traversing
b. Searching
c. Inserting
d. Sorting
9. __ is a step-by-step list of well-defined instructions for solving a particular problem.
a. Algorithm
b. Variable
c. Instruction
d. None of the above
10. In data structures the variable name is generally given in __.
a. Small letter
b. Capital letter
c. Toggle letter
d. None of the above
11. _ data structure does not require contiguous memory allocation.
a. Array
b. Linked List
c. String
d. Pointer array
12. A record is a collection of _.
a. Files
b. Arrays
c. Fields
d. Maps
13. The LIFO (Last in, First out) principle is used in which of the following data structures?
a. Stack
b. Queue
c. Linked List
d. Tree
14. Which of the following is a non-linear data structure?
a. Queue
b. Stack
c. Tree
d. Array
15. When the certain field may uniquely determine the record in a file is known as _.
a. Primary Key
b. Foreign Key
c. Digital Key
d. None of the above
16. A _ is a list of a finite number n of homogeneous data elements.
a. Array
b. Queue
c. Array
d. Tree
17. Which of the following best describes an array in C++?
a. A collection of variables of different types
b. A collection of variables of the same types
c. A dynamic data structure with linked nodes
d. None of the above
18. If an array has 10 elements, then what will be the valid range of indices?
a. 1 to 10
b. -1 to 9
c. 0 to 10
d. 0 to 9
19. In an array, which of the following is a default initial value?
a. -1
b. 0
c. 1
d. None of the above
20. Which of the following is a disadvantage of arrays?
a. Constant-time access
b. Easy traversal
c. Fixed size
d. None of the above
21. Which of the following is commonly used for array traversal in C++?
a. Do While
b. For loop
c. GOTO Statement
d. None of the above
22. The maximum number of nodes of a symmetric binary tree with a depth of 5 is _.
a. 5
b. 25
c. 31
d. 32
23. _ is very useful in situations when data is to be stored and retrieved in reverse order.
a. Stack
b. Linked List
c. Queue
d. None of the above
24. What is the space complexity of Bubble Sort?
a. O(n)
b. O(log n)
c. O(1)
d. None of the above
25. Which of the following is true about bubble sort compared to other algorithms?
a. Bubble sort is faster than quick sort.
b. Bubble sort required extra memory.
c. Bubble sort is simple but not for a large dataset.
d. All of the above
26. The time required to execute the bubble sort algorithm is proportional to _, where n is the number of input items.
a. O(n)
b. O(log n)
c. O(n²)
d. O(1)
27. The Binary Search can be used when __.
a. When the array is unsorted
b. When the array contains strings
c. When the array is sorted
d. None of the above
28. Which of the following is a disadvantage of binary search?
a. Fast searching
b. Requires sorted data
c. Works on arrays
d. Uses recursion
29. Which of the following techniques is used in binary search?
a. Hashing
b. Linear traversal
c. Divide and conquer
d. None of the above
30. Binary search can be implemented using _.
a. Only recursion
b. Only iteration
c. Both a) and b)
d. None of the above
31. Which of the following is true about pointer arithmetic with arrays?
a. Adding 1 to a pointer moves 1 byte forward
b. Adding 1 to a pointer moves to the next element.
c. Multiplying a pointer by 2 doubles the value stored.
d. None of the above
32. Which of the following high-level languages have built-in record structures?
a. PL/1
b. PASCAL
c. COBOL
d. All of the above
33. What is a linked list?
a. It is a collection of elements stored in contiguous memory.
b. It’s a stack implementation.
c. It is a collection of nodes where each node contains data and a pointer to the next node.
d. All of the above
34. Which of the following is true about linked lists?
a. It is a dynamic memory location.
b. It is a static memory location.
c. It uses less memory.
d. None of the above
35. Which of the following is disadvantage of linked list?
a. Fixed size
b. Sequential access only
c. Difficult to insert element
d. None of the above
36. What is a tree in data structure?
a. It is a linear collection of elements.
b. It is a stock implementation.
c. A hierarchical structure consists of nodes
d. None of the above
37. In a binary tree each node has at least _.
a. 1 child
b. 2 children
c. 3 children
d. None of the above
38. What is the height of a tree with only one node?
a. 0
b. 1
c. 2
d. 3
39. Accessing each element of an array only once is called ‘traversal’.
a. Selecting
b. Traversing
c. Searching
d. None of the above
40. The most efficient searching algorithm is __.
a. Binary Search
b. Linear Search
c. Reverse Search
d. None of the above
41. The node which has no parent is known as __.
a. Root
b. Child
c. LEAF
d. SUBLINGS
42. The node which has no child is known as _.
a. Root
b. Child
c. LEAF
d. SUBLINGS
43. Trees are classified according to node structure such as __.
a. Null tree
b. Binary tree
c. Ordered tree and non-ordered tree
d. All of the above
44. A tree without a node is known as __.
a. Null tree
b. Binary tree
c. Ordered tree
d. Nonordered tree
45. A tree which has a left and right child is known as __.
a. Null tree
b. Binary tree
c. Ordered tree
d. Nonordered tree
46. Children of each node are ordered from left to right, which is known as __.
a. Null tree
b. Binary tree
c. Ordered tree
d. Nonordered tree
47. Children of each node are ordered from right to left, which is known as __.
a. Null tree
b. Binary tree
c. Ordered tree
d. Nonordered tree
48. In the expression tree the leaf nodes represent __.
a. Operators
b. Operands
c. Both a) and b)
d. None of the above
49. Which of the following operations is used to remove an element from a stack?
a. Insert
b. Pop
c. Delete
d. Push
50. Which of the following operations is used to insert an element in the stack?
a. Insert
b. Pop
c. LIFO
d. Push
51. Which of the following operations is used to remove an element from a queue?
a. Enqueue
b. Pop
c. Dequeue
d. Push
52. Which of the following operations is used to insert an element in the queue?
a. Enqueue
b. Pop
c. Dequeue
d. Push
52. Which of the following is true about stacks and queues?
a. Both allow random access
b. Both are linear data structures.
c. Both are non-linear data structures.
d. None of the above
53. The number of comparisons required for bubble sorting of an array of ‘n’ elements is _.
a. n(n-1)/2
b. n/2
c. log2 n
d. log10
54. __ is the operation of rearranging the elements of an array either in increasing or decreasing order.
a. Searching
b. Sorting
c. Merging
d. None of the above
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