Arrays - BCA MCQs Quiz

1. What is the primary purpose of an array in programming?

A) Store a single value
B) Store multiple values within a single variable
C) Increase performance
D) Create functions

Correct Answer: (B) Store multiple values within a single variable.

2. What is the starting index for an array in C?

A) 1
B) 0
C) -1
D) Depends on the array size

Correct Answer: (B) 0.

3. How can an array be declared in C?

A) int array[];
B) array int[5];
C) int array(5);
D) All of the above

Correct Answer: (A) int array[].

4. What type of values can arrays hold?

A) Only integers
B) Only characters
C) Any data type
D) Only floating-point numbers

Correct Answer: (C) Any data type.

5. Which of the following is NOT an operation that can be performed on an array?

A) Traversal
B) Inheritance
C) Insertion
D) Deletion

Correct Answer: (B) Inheritance.

6. How do you access the first element of an array named "arr"?

A) arr[1]
B) arr[0]
C) arr[-1]
D) arr[first]

Correct Answer: (B) arr[0].

7. What will be the output of the following code snippet?
int arr[3] = {1, 2, 3}; printf("%d", arr[3]);

A) 0
B) 1
C) Compilation error
D) Random value

Correct Answer: (C) Compilation error.

8. In the declaration int arr[5] = {1, 2, 3}; what happens to the remaining two elements?

A) They are set to 0
B) They are left uninitialized
C) They are set to random values
D) Compilation error

Correct Answer: (A) They are set to 0.

9. Which of the following statements is true about arrays in C?

A) Arrays can hold different types of elements
B) The size of an array can change during runtime
C) Arrays have a fixed size once declared
D) Arrays are always initialized to 1

Correct Answer: (C) Arrays have a fixed size once declared.

10. What does the process of array subscripting involve?

A) Declaring an array
B) Accessing specific elements using their index
C) Initializing an array
D) Sorting an array

Correct Answer: (B) Accessing specific elements using their index.

11. What is the time complexity for retrieving any array element?

A) O(n)
B) O(log n)
C) O(1)
D) O(n²)

Correct Answer: (C) O(1).

12. How many dimensions can an array have in C?

A) 1
B) 2
C) Unlimited
D) Only 3

Correct Answer: (C) Unlimited.

13. What is the syntax to declare a one-dimensional array of integers?

A) int array[];
B) int array[10];
C) Both a and b
D) int array();

Correct Answer: (C) Both a and b.

14. Which of the following is a disadvantage of using arrays?

A) They can hold multiple types
B) They are dynamically allocated
C) Their size cannot be changed after initialization
D) They are always initialized to zero

Correct Answer: (C) Their size cannot be changed after initialization.

15. How can an array be initialized with a loop?

A) By using a while loop only
B) By using a for loop
C) By directly assigning values
D) Arrays cannot be initialized with loops

Correct Answer: (B) By using a for loop.

16. In the array declaration int arr[10]; how many elements can it hold?

A) 5
B) 10
C) 11
D) 0

Correct Answer: (B) 10.

17. What is the output of the following code? int arr[5] = {0, 1, 2, 3, 4}; printf("%d", arr[2]);

A) 0
B) 1
C) 2
D) 3

Correct Answer: (C) 2.

18. Which operation is used to combine two different arrays?

A) Merging
B) Sorting
C) Traversal
D) Searching

Correct Answer: (A) Merging.

19. What is the purpose of the loop in the following code? for (i = 0; i < 5; i++) { arr[i] = i + 1; }

A) To read values from the user
B) To initialize the array elements
C) To print the array
D) To sort the array

Correct Answer: (B) To initialize the array elements.

20. What will be the output of the following code?

 
         int arr[5] = {1, 2, 3, 4, 5}; 
         arr[2] = 10; printf("%d", arr[2]);

A) 3
B) 2
C) 10
D) 1

Correct Answer: (C) 10.

21. How are multidimensional arrays stored in memory?

A) Row-major order
B) Column-major order
C) Random order
D) They cannot be stored in memory

Correct Answer: (A) Row-major order.

22. What is a 2-dimensional array commonly referred to as?

A) Array of objects
B) Array of arrays
C) List of lists
D) Group of variables

Correct Answer: (B) Array of arrays.

23. Which of the following is a valid 2-dimensional array declaration?

A) int array[][] = {1, 2, 3, 4, 5, 6}
B) int array[3][] = {1, 2, 3, 4, 5, 6}
C) int array[3][3] = {1, 2, 3, 4, 5, 6, 7, 8, 9}
D) None of the above

Correct Answer: (C) int array[3][3] = {1, 2, 3, 4, 5, 6, 7, 8, 9};

24. In C, how are elements in 2D arrays inserted?

A) Through loops
B) Direct assignment
C) Dynamic allocation
D) Using pointers

Correct Answer: (A) Through loops.

25. Which function is used to read elements into a 2D array?

A) printf
B) scanf
C) fgets
D) malloc

Correct Answer: (B) scanf.

26. How can an element in a 2D array be updated?

A) By swapping rows
B) By modifying the required index position
C) By using pointer arithmetic
D) By re-declaring the array

Correct Answer: (B) By modifying the required index position.

27. How is the row number of an element in a 2D array removed?

A) Through reinitializing the array
B) Using loops to overwrite the elements
C) Using the free() function
D) By clearing memory space directly

Correct Answer: (B) Using loops to overwrite the elements.

28. What is the result of multiplying two matrices?

A) Addition of corresponding elements
B) Sum of row and column elements
C) Matrix multiplication results in a new matrix
D) Cannot multiply matrices

Correct Answer: (C) Matrix multiplication results in a new matrix.

29. How is matrix multiplication performed?

A) By multiplying each row of the first matrix with each row of the second
B) By multiplying each row of the first matrix with each column of the second matrix
C) By adding corresponding elements
D) By multiplying only diagonal elements

Correct Answer: (B) By multiplying each row of the first matrix with each column of the second matrix.

30. How are rows and columns specified for a 2D array in C?

A) During the declaration only
B) Through the initialization only
C) Can be omitted for rows, but columns must be specified
D) Both can be omitted

Correct Answer: (C) Can be omitted for rows, but columns must be specified.

31. What is the syntax to declare a 2D array in C?

A) data_type array_name[rows, columns];
B) data_type array_name[rows][columns];
C) data_type array_name[rows|columns];
D) None of the above

Correct Answer: (B) data_type array_name[rows][columns];

32. What is the dimension of an array defined as int arr[4][3]?

A) 12 elements
B) 4 elements
C) 3 elements
D) 7 elements

Correct Answer: (A) 12 elements.

33. Which one of the following is a correct syntax for declaring a 2D array?

A) int arr[2][3] = {{1, 2}, {3, 4}, {5, 6}};
B) int arr[2,3] = {{1, 2}, {3, 4}, {5, 6}};
C) int arr[2][3] = {1, 2, 3, 4, 5, 6};
D) int arr = {1, 2, 3, 4, 5, 6};

Correct Answer: (C) int arr[2][3] = {1, 2, 3, 4, 5, 6};

34. What will be the result of int arr[2][3] = {1, 2, 3, 4, 5, 6};?

A) Error
B) Array with 6 elements
C) 2 rows and 3 columns matrix
D) None of the above

Correct Answer: (C) 2 rows and 3 columns matrix.

35. What is a matrix in a 2D array referred to when rows and columns are equal?

A) Rectangle matrix
B) Diagonal matrix
C) Square matrix
D) Equal matrix

Correct Answer: (C) Square matrix.

36. How does matrix multiplication handle elements of the resulting matrix?

A) By multiplying corresponding elements
B) By multiplying rows of the first matrix with rows of the second
C) By summing the products of the respective row and column elements
D) None of the above

Correct Answer: (C) By summing the products of the respective row and column elements.

37. What does the second index of a 2D array represent?

A) The column number
B) The row number
C) The value of the element
D) None of the above

Correct Answer: (A) The column number.

38. When dynamically allocating a 2D array, what does malloc() return?

A) Pointer to the first element
B) Null pointer
C) Address of the last element
D) None of the above

Correct Answer: (A) Pointer to the first element.

39. What is the output of the following code: `int arr[2][2] = {{1, 2}, {3, 4}}; printf("%d", arr[1][1]);`?

A) 1
B) 2
C) 3
D) 4

Correct Answer: (D) 4.

40. What is the correct way to access the first row and second column of a 2D array named 'matrix'?

A) matrix[0, 1]
B) matrix[1][0]
C) matrix[0][1]
D) matrix[1][1]

Correct Answer: (C) matrix[0][1].

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