Engineering Questions with Answers - Multiple Choice Questions

Data Structure MCQ – Array and Array Operations

1 - Question

Which of these best describes an array?
a) A data structure that shows a hierarchical behavior
b) Container of objects of similar types
c) Arrays are immutable once initialised
d) Array is not a data structure

View Answer

Answer: b
Explanation: Array contains elements only of the same type.




2 - Question

How do you initialize an array in C?
a) int arr[3] = (1,2,3);
b) int arr(3) = {1,2,3};
c) int arr[3] = {1,2,3};
d) int arr(3) = (1,2,3);

View Answer

Answer: c
Explanation: This is the syntax to initialize an array in C.




3 - Question

How do you instantiate an array in Java?
a) int arr[] = new int(3);
b) int arr[];
c) int arr[] = new int[3];
d) int arr() = new int(3);

View Answer

Answer: c
Explanation: Note that int arr[]; is declaration whereas int arr[] = new int[3]; is to instantiate an array.




4 - Question

Which of the following is the correct way to declare a multidimensional array in Java?
a) int[] arr;
b) int arr[[]];
c) int[][]arr;
d) int[[]] arr;

View Answer

Answer: c
Explanation: The syntax to declare multidimensional array in java is either int[][] arr; or int arr[][];




5 - Question

What is the output of the following Java code?

public class array
{
public static void main(String args[])
{
int []arr = {1,2,3,4,5};
System.out.println(arr[2]);
System.out.println(arr[4]);
}
}

a) 3 and 5
b) 5 and 3
c) 2 and 4
d) 4 and 2

View Answer

Answer: a
Explanation: Array indexing starts from 0.




6 - Question

What is the output of the following Java code?

public class array
{
public static void main(String args[])
{
int []arr = {1,2,3,4,5};
System.out.println(arr[5]);
}
}

a) 4
b) 5
c) ArrayIndexOutOfBoundsException
d) InavlidInputException

View Answer

Answer: c
Explanation: Trying to access an element beyond the limits of an array gives ArrayIndexOutOfBoundsException.




7 - Question

When does the ArrayIndexOutOfBoundsException occur?
a) Compile-time
b) Run-time
c) Not an error
d) Not an exception at all

View Answer

Answer: b
Explanation: ArrayIndexOutOfBoundsException is a run-time exception and the compilation is error-free.




8 - Question

Which of the following concepts make extensive use of arrays?
a) Binary trees
b) Scheduling of processes
c) Caching
d) Spatial locality

View Answer

Answer: d
Explanation: Whenever a particular memory location is referred to, it is likely that the locations nearby are also referred, arrays are stored as contiguous blocks in memory, so if you want to access array elements, spatial locality makes it to access quickly.




9 - Question

What are the advantages of arrays? a) Objects of mixed data types can be stored b) Elements in an array cannot be sorted c) Index of first element of an array is 1 d) Easier to store elements of same data type
View Answer

Answer: d
Explanation: Arrays store elements of the same data type and present in continuous memory locations.




10 - Question

What are the disadvantages of arrays?
a) Data structure like queue or stack cannot be implemented
b) There are chances of wastage of memory space if elements inserted in an array are lesser than the allocated size
c) Index value of an array can be negative
d) Elements are sequentially accessed

View Answer

Answer: b
Explanation: Arrays are of fixed size. If we insert elements less than the allocated size, unoccupied positions can’t be used again. Wastage will occur in memory.




11 - Question

Assuming int is of 4bytes, what is the size of int arr[15];?
a) 15
b) 19
c) 11
d) 60

View Answer

Answer: d
Explanation: Since there are 15 int elements and each int is of 4bytes, we get 15*4 = 60bytes.




12 - Question

In general, the index of the first element in an array is __________
a) 0
b) -1
c) 2
d) 1

View Answer

Answer: a
Explanation: In general, Array Indexing starts from 0. Thus, the index of the first element in an array is 0.




13 - Question

Elements in an array are accessed _____________
a) randomly
b) sequentially
c) exponentially
d) logarithmically

View Answer

Answer: a
Explanation: Elements in an array are accessed randomly. In Linked lists, elements are accessed sequentially.

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