Practice 70 Java Array Programming Questions

Practice 70 Java Array Programming Questions

Q1. Write a Java program to find the largest element in an array.
  - Input: [5, 7, 2, 8, 3]
  - Expected Output: 8

Q2. Write a Java program to find the smallest element in an array.
  - Input: [12, 4, 9, 15, 6]
  - Expected Output: 4

Q3. Write a Java program to calculate the sum of all elements in an array.
  - Input: [3, 5, 7, 2]
  - Expected Output: 17

Q4. Write a Java program to calculate the average of elements in an array.
  - Input: [10, 20, 30, 40]
  - Expected Output: 25

Q5. Write a Java program to reverse an array.
  - Input: [1, 2, 3, 4, 5]
  - Expected Output: [5, 4, 3, 2, 1]

Q6. Write a Java program to check if an array is sorted.
  - Input: [1, 2, 3, 4, 5]
  - Expected Output: Sorted

Q7. Write a Java program to find the second largest element in an array.
  - Input: [10, 5, 8, 12, 7]
  - Expected Output: 10

Q8. Write a Java program to count the number of even numbers in an array.
  - Input: [1, 2, 3, 4, 5, 6]
  - Expected Output: 3

Q9. Write a Java program to count the number of odd numbers in an array.
  - Input: [1, 2, 3, 4, 5, 6]
  - Expected Output: 3

Q10. Write a Java program to merge two arrays.
   - Input: [1, 2, 3], [4, 5, 6]
   - Expected Output: [1, 2, 3, 4, 5, 6]

Q11. Write a Java program to remove duplicates from an array.
   - Input: [1, 2, 2, 3, 4, 4]
   - Expected Output: [1, 2, 3, 4]

Q12. Write a Java program to find the frequency of each element in an array.
   - Input: [1, 2, 2, 3, 3, 3]
   - Expected Output: 1 -> 1, 2 -> 2, 3 -> 3

Q13. Write a Java program to rotate an array to the right by one position.
   - Input: [1, 2, 3, 4, 5]
   - Expected Output: [5, 1, 2, 3, 4]

Q14. Write a Java program to find the common elements between two arrays.
   - Input: [1, 2, 3], [2, 3, 4]
   - Expected Output: [2, 3]

Q15. Write a Java program to find the union of two arrays.
   - Input: [1, 2, 3], [3, 4, 5]
   - Expected Output: [1, 2, 3, 4, 5]

Q16. Write a Java program to find the intersection of two arrays.
   - Input: [1, 2, 3], [2, 3, 4]
   - Expected Output: [2, 3]

Q17. Write a Java program to print all subarrays of an array.
   - Input: [1, 2, 3]
   - Expected Output: [1], [1, 2], [1, 2, 3], [2], [2, 3], [3]

Q18. Write a Java program to find the missing number in an array of 1 to N.
   - Input: [1, 2, 4, 5]
   - Expected Output: 3

Q19. Write a Java program to sort an array in ascending order.
   - Input: [5, 2, 9, 1, 5, 6]
   - Expected Output: [1, 2, 5, 5, 6, 9]

Q20. Write a Java program to sort an array in descending order.
   - Input: [5, 2, 9, 1, 5, 6]
   - Expected Output: [9, 6, 5, 5, 2, 1]

Q21. Write a Java program to find the largest contiguous subarray sum.
   - Input: [-2, 1, -3, 4, -1, 2, 1, -5, 4]
   - Expected Output: 6

Q22. Write a Java program to print the array elements in reverse order.
   - Input: [1, 2, 3, 4]
   - Expected Output: [4, 3, 2, 1]

Q23. Write a Java program to find the first non-repeating element in an array.
   - Input: [4, 5, 2, 4, 5, 7, 8]
   - Expected Output: 2

Q24. Write a Java program to find the sum of the diagonal elements of a square matrix.
   - Input: [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
   - Expected Output: 15

Q25. Write a Java program to find the index of an element in an array.
   - Input: [10, 20, 30, 40], Element: 30
   - Expected Output: 2

Q26. Write a Java program to check if two arrays are equal.
   - Input: [1, 2, 3], [1, 2, 3]
   - Expected Output: True

Q27. Write a Java program to check if an array contains a given number.
   - Input: [10, 20, 30], Number: 20
   - Expected Output: True

Q28. Write a Java program to find the sum of odd-indexed elements in an array.
   - Input: [1, 2, 3, 4, 5]
   - Expected Output: 6

Q29. Write a Java program to find the sum of even-indexed elements in an array.
   - Input: [1, 2, 3, 4, 5]
   - Expected Output: 9

Q30. Write a Java program to find the product of elements in an array.
   - Input: [1, 2, 3, 4]
   - Expected Output: 24

Q31. Write a Java program to check if an array contains duplicate elements.
   - Input: [1, 2, 3, 1]
   - Expected Output: True

Q32. Write a Java program to move all zeroes to the end of an array.
   - Input: [0, 1, 0, 3, 12]
   - Expected Output: [1, 3, 12, 0, 0]

Q33. Write a Java program to find the element that appears most in an array.
   - Input: [3, 3, 2, 1, 3, 4]
   - Expected Output: 3

Q34. Write a Java program to find the median of an array.
   - Input: [1, 2, 3, 4, 5]
   - Expected Output: 3

Q35. Write a Java program to find the sum of all positive numbers in an array.
   - Input: [-1, 2, 3, -4, 5]
   - Expected Output: 10

Q36. Write a Java program to find the sum of all negative numbers in an array.
   - Input: [-1, 2, 3, -4, 5]
   - Expected Output: -5

Q37. Write a Java program to find the difference between the largest and smallest elements in an array.
   - Input: [7, 2, 9, 4, 3]
   - Expected Output: 7

Q38. Write a Java program to count the number of positive numbers in an array.
   - Input: [-1, 2, 3, -4, 5]
   - Expected Output: 3

Q39. Write a Java program to check if an array is a palindrome.
   - Input: [1, 2, 3, 2, 1]
   - Expected Output: True

Q40. Write a Java program to remove an element from an array.
   - Input: [10, 20, 30, 40], Remove: 20
   - Expected Output: [10, 30, 40]

Q41. Write a Java program to check if an array contains only positive numbers.
   - Input: [1, 2, 3, 4]
   - Expected Output: True

Q42. Write a Java program to check if an array contains only negative numbers.
   - Input: [-1, -2, -3, -4]
   - Expected Output: True

Q43. Write a Java program to find the sum of the squares of all elements in an array.
   - Input: [1, 2, 3]
   - Expected Output: 14

Q44. Write a Java program to find the product of all elements in an array.
   - Input: [1, 2, 3, 4]
   - Expected Output: 24

Q45. Write a Java program to find the length of an array.
   - Input: [10, 20, 30, 40]
   - Expected Output: 4

Q46. Write a Java program to find the index of the smallest element in an array.
   - Input: [4, 5, 1, 2]
   - Expected Output: 2

Q47. Write a Java program to find the index of the largest element in an array.
   - Input: [4, 5, 1, 2]
   - Expected Output: 1

Q48. Write a Java program to concatenate two arrays.
   - Input: [1, 2, 3], [4, 5, 6]
   - Expected Output: [1, 2, 3, 4, 5, 6]

Q49. Write a Java program to find the element at a specific index in an array.
   - Input: [1, 2, 3, 4], Index: 2
   - Expected Output: 3

Q50. Write a Java program to print the unique elements in an array.
   - Input: [1, 2, 3, 1, 2, 4]
   - Expected Output: [3, 4]

Q51. Write a Java program to find the largest number in each row of a 2D array.
   - Input: [[1, 2], [3, 4], [5, 6]]
   - Expected Output: 2, 4, 6

Q52. Write a Java program to count the occurrences of a specific number in an array.
   - Input: [1, 2, 2, 3, 4, 2], Number: 2
   - Expected Output: 3

Q53. Write a Java program to find the even-indexed elements in an array.
   - Input: [1, 2, 3, 4, 5]
   - Expected Output: [1, 3, 5]

Q54. Write a Java program to find the odd-indexed elements in an array.
   - Input: [1, 2, 3, 4, 5]
   - Expected Output: [2, 4]

Q55. Write a Java program to replace all elements in an array with 0.
   - Input: [1, 2, 3, 4]
   - Expected Output: [0, 0, 0, 0]

Q56. Write a Java program to count the number of vowels in an array of characters.
   - Input: ['a', 'b', 'c', 'e', 'i']
   - Expected Output: 3

Q57. Write a Java program to find the maximum product of two numbers in an array.
   - Input: [1, 5, 3, 7, 9]
   - Expected Output: 63

Q58. Write a Java program to find the minimum product of two numbers in an array.
   - Input: [1, 5, 3, 7, 9]
   - Expected Output: 3

Q59. Write a Java program to find the sum of the elements at odd positions in an array.
   - Input: [1, 2, 3, 4, 5]
   - Expected Output: 6

Q60. Write a Java program to find the sum of the elements at even positions in an array.
   - Input: [1, 2, 3, 4, 5]
   - Expected Output: 9

Q61. Write a Java program to perform binary search on a sorted array.
   - Input: [1, 2, 3, 4, 5], Search: 3
   - Expected Output: Index 2

Q62. Write a Java program to count the number of elements greater than a given number in an array.
   - Input: [1, 2, 3, 4, 5], Number: 3
   - Expected Output: 2

Q63. Write a Java program to check if an array is a subset of another array.
   - Input: [1, 2, 3], [2, 3]
   - Expected Output: True

Q64. Write a Java program to check if an array is a superset of another array.
   - Input: [1, 2, 3], [2, 3]
   - Expected Output: True

Q65. Write a Java program to swap two arrays.
   - Input: [1, 2], [3, 4]
   - Expected Output: [3, 4], [1, 2]

Q66. Write a Java program to check if an array is symmetric.
   - Input: [1, 2, 3, 2, 1]
   - Expected Output: True

Q67. Write a Java program to print the sum of all elements in a 2D array.
   - Input: [[1, 2], [3, 4], [5, 6]]
   - Expected Output: 21

Q68. Write a Java program to find the product of all elements in a 2D array.
   - Input: [[1, 2], [3, 4], [5, 6]]
   - Expected Output: 720

Q69. Write a Java program to find the transpose of a matrix.
   - Input: [[1, 2], [3, 4]]
   - Expected Output: [[1, 3], [2, 4]]

Q70. Write a Java program to check if an array is a magic square.
   - Input: [[8, 1, 6], [3, 5, 7], [4, 9, 2]]
   - Expected Output: True