Practice 70 Java Recursive Methods Programming Questions, TechnoVlogs

Practice 70 Java Recursive Methods Programming Questions


Q1. Write a Java program to find the factorial of a number using recursion.
  Input:  
  Enter a number: 5

  Expected Output:  
  Factorial of 5 is 120

Q2. Write a Java program to find the sum of the digits of a number using recursion.
  Input:  
  Enter a number: 123

  Expected Output:     
  Sum of digits: 6

Q3. Write a Java program to find the power of a number using recursion.
  Input:  
  Enter the base number: 2
  Enter the exponent: 3

  Expected Output:     
  2 raised to the power of 3 is 8

Q4. Write a Java program to print Fibonacci series up to n terms using recursion.
  Input:  
  Enter number of terms: 6

  Expected Output:  
  Fibonacci series: 0 1 1 2 3 5

Q5. Write a Java program to check if a number is a palindrome using recursion.
  Input:  
  Enter a number: 121

  Expected Output:     
  The number 121 is a palindrome.
  
Q6. Write a Java program to find the greatest common divisor (GCD) of two numbers using recursion.
  Input:  
  Enter two numbers: 36 60

  Expected Output:     
  GCD of 36 and 60 is 12
  
Q7. Write a Java program to reverse a string using recursion.
  Input:  
  Enter a string: hello

  Expected Output:     
  Reversed string: olleh
  
Q8. Write a Java program to find the nth term of the Fibonacci series using recursion.
  Input:  
  Enter the position: 6

  Expected Output:     
  The 6th term of Fibonacci series is 5
  
Q9. Write a Java program to count the number of digits in a number using recursion.
  Input:  
  Enter a number: 54321

  Expected Output:     
  The number of digits is 5
  
Q10. Write a Java program to check if a number is prime using recursion.
  Input:  
  Enter a number: 7

  Expected Output:     
  7 is a prime number.

Q11. Write a Java program to find the sum of first n natural numbers using recursion.
  Input:  
  Enter a number: 5

  Expected Output:     
  Sum of first 5 natural numbers is 15

Q12. Write a Java program to find the length of a string using recursion.
  Input:  
  Enter a string: recursion

  Expected Output:     
  The length of the string is 9
  
Q13. Write a Java program to find the sum of an array using recursion.
  Input:  
  Enter array elements: 1 2 3 4 5

  Expected Output:     
  Sum of the array elements is 15

Q14. Write a Java program to find the product of an array using recursion.
  Input:  
  Enter array elements: 1 2 3 4 5

  Expected Output:     
  Product of the array elements is 120

Q15. Write a Java program to print a number in reverse order using recursion.
  Input:  
  Enter a number: 12345

  Expected Output:     
  Reversed number: 54321

Q16. Write a Java program to find the sum of even numbers up to n using recursion.
  Input:  
  Enter a number: 6

  Expected Output:     
  Sum of even numbers up to 6 is 12

Q17. Write a Java program to find the sum of odd numbers up to n using recursion.
  Input:  
  Enter a number: 6

  Expected Output:     
  Sum of odd numbers up to 6 is 9

Q18. Write a Java program to calculate the factorial of a number using tail recursion.
  Input:  
  Enter a number: 5

  Expected Output:     
  Factorial of 5 is 120

Q19. Write a Java program to find the first n prime numbers using recursion.
  Input:  
  Enter a number: 5

  Expected Output:     
  First 5 prime numbers are: 2 3 5 7 11
  
Q20. Write a Java program to find the sum of elements in a matrix using recursion.
  Input:  
  Enter matrix elements: 1 2 3 4 5 6

  Expected Output:     
  Sum of the matrix elements is 21
  
Q21. Write a Java program to find the Fibonacci series up to nth term using recursion.
  Input:  
  Enter the number of terms: 6

  Expected Output:     
  Fibonacci series: 0 1 1 2 3 5

Q22. Write a Java program to print a number in binary using recursion.
  Input:  
  Enter a number: 13

  Expected Output:     
  Binary representation of 13 is 1101
  
Q23. Write a Java program to find the maximum element in an array using recursion.
  Input:  
  Enter array elements: 2 4 5 7 1

  Expected Output:     
  Maximum element in the array is 7

Q24. Write a Java program to find the minimum element in an array using recursion.
  Input:  
  Enter array elements: 2 4 5 7 1

  Expected Output:     
  Minimum element in the array is 1
  
Q25. Write a Java program to reverse an array using recursion.
  Input:  
  Enter array elements: 1 2 3 4 5

  Expected Output:     
  Reversed array: 5 4 3 2 1
  
Q26. Write a Java program to find the sum of numbers from 1 to n using recursion.
  Input:  
  Enter a number: 4

  Expected Output:     
  Sum of numbers from 1 to 4 is 10

Q27. Write a Java program to calculate the nth power of a number using recursion.
  Input:  
  Enter the base number: 2
  Enter the exponent: 3

  Expected Output:     
  2 raised to the power of 3 is 8
  
Q28. Write a Java program to calculate the nth triangular number using recursion.
  Input:  
  Enter a number: 4

  Expected Output:     
  The 4th triangular number is 10
  
Q29. Write a Java program to check if a string is a palindrome using recursion.
  Input:  
  Enter a string: madam

  Expected Output:     
  The string "madam" is a palindrome.
  
Q30. Write a Java program to print a number pattern using recursion.
  Input:  
  Enter a number: 3

  Expected Output:     
  1 
  1 2 
  1 2 3
  
Q31. Write a Java program to find the sum of squares of numbers up to n using recursion.
  Input:  
  Enter a number: 3

  Expected Output:  
  Sum of squares up to 3 is 14
  
Q32. Write a Java program to calculate the length of a linked list using recursion.
  Input:  
  Enter elements of the linked list: 1 2 3

  Expected Output:     
  Length of the linked list is 3
  
Q33. Write a Java program to find the difference between the largest and smallest elements in an array using recursion.
  Input:  
  Enter array elements: 1 4 7 2 5

  Expected Output:     
  The difference between largest and smallest is 6
  
Q34. Write a Java program to calculate the sum of all numbers divisible by 3 using recursion.
  Input:  
  Enter a number: 6

  Expected Output:     
  Sum of numbers divisible by 3 up to 6 is 9
  
Q35. Write a Java program to count the number of vowels in a string using recursion.
  Input:  
  Enter a string: hello

  Expected Output:     
  Number of vowels in the string: 2
  
Q36. Write a Java program to print numbers in descending order from n using recursion.
  Input:  
  Enter a number: 5

  Expected Output:     
  5 4 3 2 1

Q37. Write a Java program to check if a number is a perfect number using recursion.
  Input:  
  Enter a number: 6

  Expected Output:     
  6 is a perfect number.

Q38. Write a Java program to calculate the nth Fibonacci number using recursion.
  Input:  
  Enter a number: 5

  Expected Output:     
  The 5th Fibonacci number is 5

Q39. Write a Java program to find the sum of the first n odd numbers using recursion.
  Input:  
  Enter a number: 4

  Expected Output:     
  Sum of first 4 odd numbers is 16
  
Q40. Write a Java program to print a pattern of stars using recursion.
  Input:  
  Enter a number: 3

  Expected Output:  
  * 
  * *
  * * *

Q41. Write a Java program to find the least common multiple (LCM) of two numbers using recursion.
  Input:  
  Enter two numbers: 4 6

  Expected Output:     
  LCM of 4 and 6 is 12
  
Q42. Write a Java program to find the sum of the first n even numbers using recursion.
  Input:  
  Enter a number: 4

  Expected Output:    
  Sum of first 4 even numbers is 20
  
Q43. Write a Java program to find the second largest number in an array using recursion.
  Input:  
  Enter array elements: 2 4 1 5 3

  Expected Output:     
  Second largest number in the array is 4
  
Q44. Write a Java program to find the sum of digits of a number using recursion.
  Input:  
  Enter a number: 54321

  Expected Output:     
  Sum of digits is 15
  
Q45. Write a Java program to check if a number is an Armstrong number using recursion.
  Input:  
  Enter a number: 153

  Expected Output:     
  153 is an Armstrong number.
  
Q46. Write a Java program to find the product of digits of a number using recursion.
  Input:  
  Enter a number: 123

  Expected Output:     
  Product of digits is 6
  
Q47. Write a Java program to print a pyramid pattern using recursion.
  Input:  
  Enter a number: 3

  Expected Output:  
    * 
   * * 
  * * *

Q48. Write a Java program to find the greatest element in a set using recursion.
  Input:  
  Enter set elements: 1 4 6 2

  Expected Output:     
  Greatest element is 6
  
Q49. Write a Java program to calculate the sum of the series 1 + 1/2 + 1/3 + ... + 1/n using recursion.
  Input:  
  Enter a number: 3

  Expected Output:     
  Sum of the series is 1.83333
  
Q50. Write a Java program to check if a number is divisible by 2 using recursion.
  Input:  
  Enter a number: 4

  Expected Output:     
  The number is divisible by 2.
  
Q51. Write a Java program to print the factors of a number using recursion.
  Input:  
  Enter a number: 6

  Expected Output:     
  Factors of 6 are: 1 2 3 6
  
Q52. Write a Java program to check if a string contains only digits using recursion.
  Input:  
  Enter a string: 12345

  Expected Output:     
  The string contains only digits.

Q53. Write a Java program to find the nth triangular number using recursion.
  Input:  
  Enter a number: 4

  Expected Output:     
  The 4th triangular number is 10
  
Q54. Write a Java program to find the sum of first n odd numbers using recursion.
  Input:  
  Enter a number: 4

  Expected Output:     
  Sum of first 4 odd numbers is 16
  
Q55. Write a Java program to calculate the factorial of a number using recursion.
  Input:  
  Enter a number: 5

  Expected Output:     
  Factorial of 5 is 120
  
Q56. Write a Java program to print the first n natural numbers using recursion.
  Input:  
  Enter a number: 3

  Expected Output:     
  1 2 3
  
Q57. Write a Java program to find the sum of squares of numbers up to n using recursion.
  Input:  
  Enter a number: 3

  Expected Output:     
  Sum of squares up to 3 is 14
  
Q58. Write a Java program to check if a number is a perfect square using recursion.
  Input:  
  Enter a number: 16

  Expected Output:     
  16 is a perfect square.

Q59. Write a Java program to reverse a string using recursion.
  Input:  
  Enter a string: hello

  Expected Output:     
  Reversed string: olleh
  
Q60. Write a Java program to print a diamond pattern using recursion.
  Input:  
  Enter a number: 3

  Expected Output:  
    *   
   * *  
  * * *  
   * *  
    *      

Q61. Write a Java program to find the sum of all digits of a number using recursion.
  Input:  
  Enter a number: 123

  Expected Output:     
  Sum of digits is 6

Q62. Write a Java program to check if a string is a palindrome using recursion.
  Input:  
  Enter a string: madam

  Expected Output:     
  The string "madam" is a palindrome.
  
Q63. Write a Java program to print the factorial of a number using recursion.
  Input:  
  Enter a number: 5

  Expected Output:     
  Factorial of 5 is 120
  
Q64. Write a Java program to find the sum of elements in an array using recursion.
  Input:  
  Enter array elements: 1 2 3 4

  Expected Output:     
  Sum of the array elements is 10
  
Q65. Write a Java program to calculate the nth Fibonacci number using recursion.
  Input:  
  Enter a number: 5

  Expected Output:     
  Fibonacci number at position 5 is 5
  
Q66. Write a Java program to check if a number is even or odd using recursion.
  Input:  
  Enter a number: 4

  Expected Output:     
  The number is even.
  
Q67. Write a Java program to find the largest element in an array using recursion.
  Input:  
  Enter array elements: 1 2 5 3

  Expected Output:     
  Largest element is 5
  
Q68. Write a Java program to calculate the sum of cubes of the first n natural numbers using recursion.
  Input:  
  Enter a number: 3

  Expected Output:     
  Sum of cubes up to 3 is 36
  
Q69. Write a Java program to calculate the sum of all even digits of a number using recursion.
  Input:  
  Enter a number: 123456

  Expected Output:     
  Sum of even digits is 12
  
Q70. Write a Java program to print a number pattern (reverse) using recursion.
  Input:  
  Enter a number: 5

  Expected Output:     
  5 4 3 2 1

Share on Social Media