Arrays in C : MCQs & PYQs with Explanation

Option A

In C, an array is initialized using square brackets [] to specify its size and curly braces {} to provide initial values. The statement int LA[5] = {1,2,3,4}; correctly follows this syntax. Even though the array size is 5 and only 4 values are provided, the remaining element is automatically initialized to 0.

Option B

The process of accessing each element of an array one by one in order to perform an operation such as printing, updating, or calculating is called Array Traversal.

• Searching refers to the operation of finding a specific element in the array.
• Merging refers to the operation of combining two arrays.

Option B

The array arr is initially defined as {1,2,3,4,5}, which contains 5 elements. The statements arr[1]=22; and arr[3]=44; only update the values at index 1 and index 3 of the existing array.
The array’s length remains unchanged by element assignments. It still contains 5 elements.

Option B

An array is a data structure that stores a collection of elements of the same data type (homogeneous) in contiguous memory locations.

• Hierarchical behavior is shown by data structures like trees.
• Containers of heterogeneous (different) types describe structures or classes.

Option A

In C, an array is declared using the data type, array name, and size enclosed in square brackets []. 
Syntax:
Data_Type Array_Name[Array_Size];
The statement int suraku[20]; follows the correct syntax for array declaration.

Option D

The name of a 1-D array in C is a constant pointer to the type of array. This means it holds the address of the first element and cannot be changed to point to another location. For example, if you have int arr[6];, then arr is a constant pointer to int, always pointing to arr[0] and cannot be reassigned.

Option C

An Array is a Homogeneous Data Structure, meaning it stores elements of the same data type. In most programming languages like C, C++, and Java, array indexing starts from 0.

Option D

In C/C++, a 2D array is stored in row-major order, which means elements are filled row by row.
Given array : int Data[2][4] = {10, 20, 30, 40, 50, 60, 70, 80};. This will be stored as:

So, the indexing becomes:

• Data[0][0] = 10
• Data[0][1] = 20
• Data[0][2] = 30
• Data[0][3] = 40
• Data[1][0] = 50
• Data[1][1] = 60
• Data[1][2] = 70
• Data[1][3] = 80

Option D

In a dynamic array, elements are stored next to each other (contiguous) in memory, just like a regular array (static array). The difference is that the size of a dynamic array is decided at runtime and memory is allocated dynamically in the heap section.

Option C

Static Arrays have a fixed size that must be defined at compile time. If fewer elements are stored than the allocated size, the unused locations remain empty, leading to wastage of memory space. This is the main disadvantage of static arrays.

• Queue and stack can be implemented using both static and dynamic arrays.
• Array index values cannot be negative in C.
• Arrays support random access, not only sequential access.

Option D

A 2D array is an array of arrays, where each element of the main array is itself another array. It is commonly used to store data in the form of rows and columns, like a table or matrix.

• Single row represents a 1D array.
• Single column is also a 1D array.
• A 2D array can store any data type, not only integers.

Option A

In C, the array name itself behaves like a pointer constant. This means it holds the address of the first element of the array.

Option C

In C, a two-dimensional array is essentially an array of one-dimensional arrays. Therefore, the name of a 2-D array represents the address of its first row, which itself is a 1-D array. Since the number of columns is fixed in memory layout, each row is treated as a 1-D array of fixed column size.

Option B

Arrays use the random-access method to access elements. This means any element of the array can be accessed directly using its index, without accessing previous elements. Due to this direct indexing and contiguous memory allocation, accessing arr[i] takes constant time (O(1)).

• Sequential Access is used in data structures like linked lists, where elements are accessed one after another starting from the first node.

Option B

An array is a data structure that stores a fixed number of elements of similar types. This means every value inside an array should be either all integers, all floats, all characters, etc. This property is called homogeneous because the elements are similar in type. 

• Arrays cannot store elements of different data types i.e., heterogeneous type.