Practice 70 Java Numbers Programming Questions

Practice 70 Java Numbers Programming Questions

Q1. Write a Java program to check if a number is positive, negative, or zero.
   Input:  
   Enter a number: -5

   Expected Output:      
   The number -5 is negative

   
Q2. Write a Java program to find the largest number among three numbers.
   Input:  
   Enter first number: 10
   Enter second number: 20
   Enter third number: 15

   Expected Output:      
   The largest number is 20

Q3. Write a Java program to check if a number is even or odd.
   Input:  
   Enter a number: 7

   Expected Output:      
   7 is odd

Q4. Write a Java program to find the factorial of a number.
   Input:  
   Enter a number: 5

   Expected Output:      
   Factorial of 5 is 120

Q5. Write a Java program to check whether a number is prime or not.
   Input:  
   Enter a number: 11

   Expected Output:      
   11 is a prime number

Q6. Write a Java program to calculate the sum of digits of a number.
   Input:  
   Enter a number: 123

   Expected Output:     
   Sum of digits: 6

Q7. Write a Java program to find the reverse of a number.
   Input:  
   Enter a number: 12345

   Expected Output:      
   Reverse of the number is 54321

Q8. Write a Java program to check if a number is palindrome or not.
   Input:  
   Enter a number: 121

   Expected Output:      
   121 is a palindrome

Q9. Write a Java program to find the sum of all natural numbers up to a given number.
   Input:  
   Enter a number: 5

   Expected Output:      
   Sum of natural numbers up to 5 is 15

Q10. Write a Java program to check if a number is an Armstrong number.
   Input:  
   Enter a number: 153

   Expected Output:      
   153 is an Armstrong number

Q11. Write a Java program to find the greatest common divisor (GCD) of two numbers.
   Input:  
   Enter first number: 12
   Enter second number: 18

   Expected Output:      
   GCD of 12 and 18 is 6

Q12. Write a Java program to find the least common multiple (LCM) of two numbers.
   Input:  
   Enter first number: 12
   Enter second number: 15

   Expected Output:      
   LCM of 12 and 15 is 60

Q13. Write a Java program to find the sum of first n even numbers.
   Input:  
   Enter a number: 5

   Expected Output:      
   Sum of first 5 even numbers is 30

Q14. Write a Java program to find the sum of first n odd numbers.
   Input:  
   Enter a number: 5

   Expected Output:      
   Sum of first 5 odd numbers is 25

Q15. Write a Java program to print multiplication table of a number.
   Input:  
   Enter a number: 5

   Expected Output:      
   5 x 1 = 5
   5 x 2 = 10
   5 x 3 = 15
   5 x 4 = 20
   5 x 5 = 25

Q16. Write a Java program to calculate the sum of all even numbers in an array.
   Input:  
   Enter array of numbers: 1, 2, 3, 4, 5, 6

   Expected Output:      
   Sum of even numbers: 12

Q17. Write a Java program to calculate the sum of all odd numbers in an array.
   Input:  
   Enter array of numbers: 1, 2, 3, 4, 5, 6

   Expected Output:      
   Sum of odd numbers: 9

Q18. Write a Java program to find the smallest number in an array.
   Input:  
   Enter array of numbers: 2, 5, 7, 1

   Expected Output:      
   Smallest number in the array is 1

Q19. Write a Java program to calculate the average of numbers in an array.
   Input:  
   Enter array of numbers: 1, 2, 3, 4, 5

   Expected Output:      
   Average of numbers: 3.0

Q20. Write a Java program to find the second largest number in an array.
   Input:  
   Enter array of numbers: 10, 5, 20, 15

   Expected Output:      
   Second largest number is 15

Q21. Write a Java program to find the number of digits in a number.
   Input:  
   Enter a number: 12345

   Expected Output:      
   Number of digits: 5

Q22. Write a Java program to count the number of even numbers in an array.
   Input:  
   Enter array of numbers: 1, 2, 3, 4, 5, 6

   Expected Output:      
   Number of even numbers: 3

Q23. Write a Java program to count the number of odd numbers in an array.
   Input:  
   Enter array of numbers: 1, 2, 3, 4, 5, 6

   Expected Output:      
   Number of odd numbers: 3

Q24. Write a Java program to find the product of all numbers in an array.
   Input:  
   Enter array of numbers: 2, 3, 4

   Expected Output:      
   Product of numbers: 24

Q25. Write a Java program to check whether a number is a perfect number or not.
   Input:  
   Enter a number: 6

   Expected Output:      
   6 is a perfect number

Q26. Write a Java program to check if a number is divisible by 5 or not.
   Input:  
   Enter a number: 10

   Expected Output:      
   10 is divisible by 5

Q27. Write a Java program to check if a number is divisible by 7 or not.
   Input:  
   Enter a number: 14

   Expected Output:  
   14 is divisible by 7

Q28. Write a Java program to calculate the square of a number.
   Input:  
   Enter a number: 4

   Expected Output:      
   Square of 4 is 16

Q29. Write a Java program to calculate the cube of a number.
   Input:  
   Enter a number: 3

   Expected Output:      
   Cube of 3 is 27

Q30. Write a Java program to find the sum of even numbers between 1 and n.
   Input:  
   Enter a number: 10

   Expected Output:      
   Sum of even numbers between 1 and 10 is 30

Q31. Write a Java program to find the sum of odd numbers between 1 and n.
   Input:  
   Enter a number: 10

   Expected Output:      
   Sum of odd numbers between 1 and 10 is 25

Q32. Write a Java program to find the number of vowels in a given string.
   Input:  
   Enter a string: Hello World

   Expected Output:      
   Number of vowels: 3

Q33. Write a Java program to check if a number is an Armstrong number or not.
   Input:  
   Enter a number: 370

   Expected Output:      
   370 is an Armstrong number

Q34. Write a Java program to convert a decimal number to binary.
   Input:  
   Enter a decimal number: 5

   Expected Output:      
   Binary equivalent of 5 is 101

Q35. Write a Java program to convert a binary number to decimal.
   Input:  
   Enter a binary number: 101

   Expected Output:      
   Decimal equivalent of 101 is 5

Q36. Write a Java program to convert a decimal number to hexadecimal.
   Input:  
   Enter a decimal number: 15

   Expected Output:      
   Hexadecimal equivalent of 15 is F

Q37. Write a Java program to calculate the square root of a number.
   Input:  
   Enter a number: 16

   Expected Output:      
   Square root of 16 is 4

Q38. Write a Java program to check if a number is a power of 2.
   Input:  
   Enter a number: 16

   Expected Output:      
   16 is a power of 2

Q39. Write a Java program to find the highest power of 2 less than or equal to a given number.
   Input:  
   Enter a number: 50

   Expected Output:      
   Highest power of 2 less than or equal to 50 is 32

Q40. Write a Java program to check if a number is a perfect square.
   Input:  
   Enter a number: 25

   Expected Output:      
   25 is a perfect square

Q41. Write a Java program to find the square of a number without using Math.pow.
   Input:      
   Enter a number: 5

   Expected Output:      
   Square of 5 is 25

Q42. Write a Java program to find the cube of a number without using Math.pow.
   Input:  
   Enter a number: 4

   Expected Output:      
   Cube of 4 is 64

Q43. Write a Java program to find the sum of odd digits in a number.
   Input:  
   Enter a number: 1357

   Expected Output:      
   Sum of odd digits: 16

Q44. Write a Java program to find the sum of even digits in a number.
   Input:  
   Enter a number: 2468

   Expected Output:      
   Sum of even digits: 20

Q45. Write a Java program to remove all even digits from a number.
   Input:  
   Enter a number: 123456

   Expected Output:      
   Number after removing even digits: 135

Q46. Write a Java program to count the number of even digits in a number.
   Input:  
   Enter a number: 123456

   Expected Output:      
   Number of even digits: 3

Q47. Write a Java program to find the sum of prime numbers between 1 and n.
   Input:  
   Enter a number: 10

   Expected Output:      
   Sum of prime numbers between 1 and 10 is 17

Q48. Write a Java program to find all the factors of a number.
   Input:  
   Enter a number: 12

   Expected Output:      
   Factors of 12 are: 1, 2, 3, 4, 6, 12

Q49. Write a Java program to find the sum of the first n prime numbers.
   Input:  
   Enter a number: 5

   Expected Output:      
   Sum of the first 5 prime numbers is 28

Q50. Write a Java program to find the sum of squares of numbers up to a given number.
   Input:  
   Enter a number: 3

   Expected Output:  
   Sum of squares: 14

Q51. Write a Java program to calculate the cube root of a number.
   Input:  
   Enter a number: 27

   Expected Output:      
   Cube root of 27 is 3

Q52. Write a Java program to generate the Fibonacci sequence up to a given number.
   Input:  
   Enter a number: 10

   Expected Output:      
   Fibonacci sequence up to 10: 0, 1, 1, 2, 3, 5, 8

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

   Expected Output:      
   Factorial of 4 is 24

Q54. Write a Java program to find the sum of digits of a number using recursion.
   Input:  
   Enter a number: 123

   Expected Output:      
   Sum of digits: 6

Q55. Write a Java program to calculate the power of a number without using Math.pow.
   Input:  
   Enter a base number: 2
   Enter an exponent: 3

   Expected Output:      
   2 raised to the power 3 is 8

Q56. Write a Java program to check whether a number is divisible by both 3 and 5.
   Input:  
   Enter a number: 15

   Expected Output:      
   15 is divisible by both 3 and 5

Q57. Write a Java program to find the difference between the sum of squares of first n natural numbers and the square of their sum.
   Input:  
   Enter a number: 5

   Expected Output:      
   Difference is 15

Q58. Write a Java program to find the sum of all factors of a number.
   Input:  
   Enter a number: 12

   Expected Output:      
   Sum of factors of 12 is 28

Q59. Write a Java program to check if a number is divisible by 9 or not.
   Input:  
   Enter a number: 18

   Expected Output:      
   18 is divisible by 9

Q60. Write a Java program to find the number of divisors of a number.
   Input:  
   Enter a number: 12

   Expected Output:      
   Number of divisors of 12 is 6

Q61. Write a Java program to find if a number is divisible by 4.
   Input:  
   Enter a number: 16

   Expected Output:      
   16 is divisible by 4

Q62. Write a Java program to check whether a number is a multiple of 3 or not.
   Input:  
   Enter a number: 9

   Expected Output:      
   9 is a multiple of 3

Q63. Write a Java program to calculate the sum of the digits of a number using streams.
   Input:  
   Enter a number: 234

   Expected Output:      
   Sum of digits: 9

Q64. Write a Java program to generate Fibonacci series using streams.
   Input:  
   Enter the limit: 5

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

Q65. Write a Java program to check if a number is divisible by 6.
   Input:  
   Enter a number: 18

   Expected Output:      
   18 is divisible by 6

Q66. Write a Java program to check whether a number is divisible by both 2 and 3.
   Input:  
   Enter a number: 12

   Expected Output:      
   12 is divisible by both 2 and 3

Q67. Write a Java program to print all prime numbers up to a given number.
   Input:  
   Enter a number: 10

   Expected Output:      
   Prime numbers up to 10 are: 2, 3, 5, 7

Q68. Write a Java program to find the factorial of a number using a loop.
   Input:  
   Enter a number: 6

   Expected Output:      
   Factorial of 6 is 720

Q69. Write a Java program to calculate the sum of squares of the first n natural numbers.
   Input:  
   Enter a number: 4

   Expected Output:  
   Sum of squares: 30

Q70. Write a Java program to find the sum of even numbers in a given range.
   Input:  
   Enter a range: 1 to 10

   Expected Output:      
   Sum of even numbers in the range 1 to 10 is 30