Practice 50 JavaScript Recursion Programming Questions, TechnoVlogs

Practice 50 JavaScript Recursion Programming Questions


Q1. Write a JavaScript program to find the factorial of a number using recursion.  
Input: factorial(5)  
Expected Output: 120

Q2. Write a JavaScript program to calculate the nth Fibonacci number using recursion.  
Input: fibonacci(6)  
Expected Output: 8

Q3. Write a JavaScript program to calculate the sum of all elements in an array using recursion.  
Input: sumArray([1, 2, 3, 4])  
Expected Output: 10

Q4. Write a JavaScript program to reverse a string using recursion.  
Input: reverseString("hello")  
Expected Output: "olleh"

Q5. Write a JavaScript program to calculate the power of a number using recursion.  
Input: power(2, 3)  
Expected Output: 8

Q6. Write a JavaScript program to find the sum of digits of a number using recursion.  
Input: sumDigits(123)  
Expected Output: 6

Q7. Write a JavaScript program to check if a string is a palindrome using recursion.  
Input: isPalindrome("racecar")  
Expected Output: true

Q8. Write a JavaScript program to calculate the greatest common divisor (GCD) of two numbers using recursion.  
Input: gcd(48, 18)  
Expected Output: 6

Q9. Write a JavaScript program to count the number of vowels in a string using recursion.  
Input: countVowels("hello")  
Expected Output: 2

Q10. Write a JavaScript program to flatten a nested array using recursion.  
Input: flatten([1, [2, [3, 4]]])  
Expected Output: [1, 2, 3, 4]

Q11. Write a JavaScript program to calculate the length of a string using recursion.  
Input: stringLength("hello")  
Expected Output: 5

Q12. Write a JavaScript program to check if an array is sorted using recursion.  
Input: isSorted([1, 2, 3, 4])  
Expected Output: true

Q13. Write a JavaScript program to count the occurrences of a character in a string using recursion.  
Input: countChar("hello", "l")  
Expected Output: 2

Q14. Write a JavaScript program to calculate the product of an array of numbers using recursion.  
Input: productArray([1, 2, 3, 4])  
Expected Output: 24

Q15. Write a JavaScript program to calculate the sum of even numbers in an array using recursion.  
Input: sumEven([1, 2, 3, 4])  
Expected Output: 6

Q16. Write a JavaScript program to convert a decimal number to binary using recursion.  
Input: decimalToBinary(10)  
Expected Output: "1010"

Q17. Write a JavaScript program to count the number of elements in a nested array using recursion.  
Input: countElements([1, [2, [3, 4]]])  
Expected Output: 4

Q18. Write a JavaScript program to find the minimum element in an array using recursion.  
Input: findMin([3, 5, 1, 4])  
Expected Output: 1

Q19. Write a JavaScript program to calculate the sum of a geometric series using recursion.  
Input: geometricSum(3, 2)  
Expected Output: 7 (1 + 2 + 4)

Q20. Write a JavaScript program to replace all occurrences of a character in a string using recursion.  
Input: replaceChar("hello", "l", "x")  
Expected Output: "hexxo"

Q21. Write a JavaScript program to find the nth triangular number using recursion.  
Input: triangularNumber(5)  
Expected Output: 15

Q22. Write a JavaScript program to calculate the harmonic sum of n using recursion.  
Input: harmonicSum(3)  
Expected Output: 1.833 (1 + 1/2 + 1/3)

Q23. Write a JavaScript program to count the number of zeros in a number using recursion.  
Input: countZeros(10204)  
Expected Output: 2

Q24. Write a JavaScript program to find the depth of a nested array using recursion.  
Input: arrayDepth([1, [2, [3, 4]]])  
Expected Output: 3

Q25. Write a JavaScript program to calculate the sum of odd numbers in an array using recursion.  
Input: sumOdd([1, 2, 3, 4, 5])  
Expected Output: 9

Q26. Write a JavaScript program to remove duplicates from an array using recursion.  
Input: removeDuplicates([1, 2, 2, 3, 3, 4])  
Expected Output: [1, 2, 3, 4]

Q27. Write a JavaScript program to calculate the sum of squares of numbers in an array using recursion.  
Input: sumOfSquares([1, 2, 3])  
Expected Output: 14

Q28. Write a JavaScript program to find the first uppercase letter in a string using recursion.  
Input: firstUppercase("helloWorld")  
Expected Output: "W"

Q29. Write a JavaScript program to calculate the sum of numbers from 1 to n using recursion.  
Input: sumToN(10)  
Expected Output: 55

Q30. Write a JavaScript program to remove all non-alphanumeric characters from a string using recursion.  
Input: cleanString("he!!llo@")  
Expected Output: "hello"

Q31. Write a JavaScript program to check if a number is a power of two using recursion.  
Input: isPowerOfTwo(16)  
Expected Output: true  

Input: isPowerOfTwo(18)  
Expected Output: false

Q32. Write a JavaScript program to calculate the nth Lucas number using recursion.  
Input: lucasNumber(5)  
Expected Output: 11

Q33. Write a JavaScript program to reverse an array using recursion.  
Input: reverseArray([1, 2, 3, 4])  
Expected Output: [4, 3, 2, 1]

Q34. Write a JavaScript program to calculate the binomial coefficient (nCr) using recursion.  
Input: binomialCoefficient(5, 2)  
Expected Output: 10

Q35. Write a JavaScript program to check if a number is a palindrome using recursion.  
Input: isNumberPalindrome(121)  
Expected Output: true  

Input: isNumberPalindrome(123)  
Expected Output: false

Q36. Write a JavaScript program to calculate the product of two numbers without using multiplication, using recursion.  
Input: multiply(3, 4)  
Expected Output: 12

Q37. Write a JavaScript program to find the nth Catalan number using recursion.  
Input: catalanNumber(3)  
Expected Output: 5

Q38. Write a JavaScript program to find the maximum depth of a binary tree represented as a nested array using recursion.  
Input: maxDepth([1, [2, [3]]])  
Expected Output: 3

Q39. Write a JavaScript program to calculate the sum of an arithmetic series using recursion.  
Input: arithmeticSum(3, 5)  
Expected Output: 15 (3 + 4 + 5)

Q40. Write a JavaScript program to count the number of uppercase letters in a string using recursion.  
Input: countUppercase("HeLLo")  
Expected Output: 3

Q41. Write a JavaScript program to calculate the product of digits in a number using recursion.  
Input: productOfDigits(234)  
Expected Output: 24

Q42. Write a JavaScript program to calculate the length of a nested array using recursion.  
Input: nestedArrayLength([1, [2, [3, 4]], 5])  
Expected Output: 5

Q43. Write a JavaScript program to find the sum of natural numbers up to n that are divisible by 3 or 5 using recursion.  
Input: sumDivisibleByThreeOrFive(10)  
Expected Output: 33

Q44. Write a JavaScript program to calculate the LCM (least common multiple) of two numbers using recursion.  
Input: lcm(12, 15)  
Expected Output: 60

Q45. Write a JavaScript program to find the index of the first occurrence of a target in an array using recursion.  
Input: findIndex([1, 2, 3, 4, 5], 3)  
Expected Output: 2

Q46. Write a JavaScript program to calculate the nth tetrahedral number using recursion.  
Input: tetrahedralNumber(4)  
Expected Output: 10

Q47. Write a JavaScript program to find the number of consonants in a string using recursion.  
Input: countConsonants("hello world")  
Expected Output: 7

Q48. Write a JavaScript program to implement recursive binary search in an array.  
Input: binarySearch([1, 2, 3, 4, 5], 3)  
Expected Output: 2

Q49. Write a JavaScript program to split a string into an array of words using recursion.  
Input: splitWords("hello world")  
Expected Output: ["hello", "world"]

Q50. Write a JavaScript program to calculate the digital root of a number using recursion.  
Input: digitalRoot(9875)  
Expected Output: 2  

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