Practice 100 Java Basic Programming Questions, TechnoVlogs

Practice 100 Java Basic Programming Questions


Q1. Write a Java program to print "Hello, World!".
Input: No input  
Expected Output:  
Hello, World!

Q2. Write a Java program to print the sum of two numbers.  
Input:  
Enter first number: 5  
Enter second number: 3

Expected Output:  
Sum = 8

Q3. Write a Java program to swap two numbers without using a third variable.  
Input:  
Enter first number: 4  
Enter second number: 7
 
Expected Output:  
After swapping:  
First number = 7  
Second number = 4

Q4. Write a Java program to find the largest of two numbers.  
Input:  
Enter first number: 12  
Enter second number: 8


Expected Output:  
Largest number = 12

Q5. Write a Java program to check whether a number is even or odd.  
Input:  
Enter a number: 11

Expected Output:  
11 is an odd number.

Q6. Write a Java program to calculate the area of a rectangle.  
Input:  
Enter length: 5  
Enter width: 6

Expected Output:  
Area of rectangle = 30

Q7. Write a Java program to calculate the area of a circle.  
Input:  
Enter radius: 7

Expected Output:  
Area of circle = 153.93804

Q8. Write a Java program to print the multiplication table of a number.  
Input:  
Enter a number: 3

Expected Output:  
3 x 1 = 3  
3 x 2 = 6  
3 x 3 = 9  
...  
3 x 10 = 30

Q9. Write a Java program to convert Celsius to Fahrenheit.  
Input:  
Enter temperature in Celsius: 25

Expected Output:  
Temperature in Fahrenheit: 77.0

Q10. Write a Java program to reverse a string.  
Input:  
Enter a string: Hello

Expected Output:  
Reversed string: olleH

Q11. Write a Java program to find the sum of digits of a number.  
Input:  
Enter a number: 123

Expected Output:  
Sum of digits = 6

Q12. Write a Java program to check if a number is positive or negative.  
Input:  
Enter a number: -7

Expected Output:  
The number is negative.

Q13. Write a Java program to check whether a character is a vowel or consonant.  
Input:  
Enter a character: a

Expected Output:  
The character 'a' is a vowel.

Q14. Write a Java program to find the factorial of a number.  
Input:  
Enter a number: 5

Expected Output:  
Factorial of 5 = 120

Q15. Write a Java program to check whether a number is prime.  
Input:  
Enter a number: 7

Expected Output:  
7 is a prime number.

Q16. Write a Java program to print Fibonacci series up to N terms.  
Input:  
Enter the number of terms: 5

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

Q17. Write a Java program to count the number of digits in a number.  
Input:  
Enter a number: 45678

Expected Output:  
Number of digits = 5

Q18. Write a Java program to find the greatest of three numbers.  
Input:  
Enter three numbers: 5 9 3

Expected Output:  
The greatest number is 9.

Q19. Write a Java program to check if a number is palindrome.  
Input:  
Enter a number: 121

Expected Output:  
121 is a palindrome.

Q20. Write a Java program to calculate the sum of N natural numbers.  
Input:  
Enter N: 10

Expected Output:  
Sum = 55

Q21. Write a Java program to find the average of N numbers.  
Input:  
Enter the count of numbers: 4  
Enter numbers: 5 10 15 20

Expected Output:  
Average = 12.5

Q22. Write a Java program to find the GCD of two numbers.  
Input:  
Enter two numbers: 56 98

Expected Output:  
GCD = 14

Q23. Write a Java program to calculate the simple interest.  
Input:  
Enter principal: 1000  
Enter rate: 5  
Enter time: 2

Expected Output:  
Simple Interest = 100.0

Q24. Write a Java program to check whether a number is divisible by 5 and 11.  
Input:  
Enter a number: 55

Expected Output:  
55 is divisible by both 5 and 11.

Q25. Write a Java program to convert kilometers to miles.  
Input:  
Enter distance in kilometers: 5

Expected Output:  
Distance in miles: 3.106855

Q26. Write a Java program to print a pattern of stars.  
Input:  
Enter the number of rows: 4

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

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

Expected Output:  
Result = 8

Q28. Write a Java program to find the largest and smallest numbers in an array.  
Input:  
Enter array elements: 2 8 1 6 3

Expected Output:  
Largest number = 8  
Smallest number = 1

Q29. Write a Java program to calculate the compound interest.  
Input:  
Enter principal: 1000  
Enter rate: 5  
Enter time: 2  
Enter number of times interest applied per time period: 4

Expected Output:  
Compound Interest = 1040.60401

Q30. Write a Java program to print ASCII value of a character.  
Input:  
Enter a character: A

Expected Output:  
ASCII value of A = 65

Q31. Write a Java program to convert a decimal number to binary.  
Input:  
Enter a decimal number: 10

Expected Output:  
Binary representation = 1010

Q32. Write a Java program to find the second largest number in an array.  
Input:  
Enter array elements: 5 3 9 1 6

Expected Output:  
Second largest number = 6

Q33. Write a Java program to remove vowels from a string.  
Input:  
Enter a string: Programming

Expected Output:  
String after removing vowels: Prgrmmng

Q34. Write a Java program to count the frequency of characters in a string.  
Input:  
Enter a string: apple

Expected Output:  
Frequency of a: 1  
Frequency of p: 2  
Frequency of l: 1  
Frequency of e: 1

Q35. Write a Java program to calculate the sum of elements in an array.  
Input:  
Enter array elements: 1 2 3 4 5

Expected Output:  
Sum of array elements = 15

Q36. Write a Java program to reverse a number.  
Input:  
Enter a number: 1234

Expected Output:  
Reversed number = 4321

Q37. Write a Java program to find the length of a string without using the built-in function.  
Input:  
Enter a string: Hello

Expected Output:  
Length of the string = 5

Q38. Write a Java program to find the LCM of two numbers.  
Input:  
Enter two numbers: 12 15

Expected Output:  
LCM = 60

Q39. Write a Java program to find the sum of elements on the diagonal of a matrix.  
Input:  
Enter matrix elements:  
1 2 3  
4 5 6  
7 8 9

Expected Output:  
Sum of diagonal elements = 15

Q40. Write a Java program to find the transpose of a matrix.  
Input:  
Enter matrix elements:  
1 2 3  
4 5 6

Expected Output:  
Transpose:  
1 4  
2 5  
3 6

Q41. Write a Java program to check if a string is a palindrome.  
Input:  
Enter a string: madam

Expected Output:  
The string is a palindrome.

Q42. Write a Java program to count the number of vowels and consonants in a string.  
Input:  
Enter a string: Java

Expected Output:  
Vowels: 2  
Consonants: 2

Q43. Write a Java program to find the sum of even and odd numbers in an array.  
Input:  
Enter array elements: 1 2 3 4 5

Expected Output:  
Sum of even numbers = 6  
Sum of odd numbers = 9

Q44. Write a Java program to calculate the percentage of marks.  
Input:  
Enter marks in 5 subjects: 80 90 70 85 95

Expected Output:  
Percentage = 84.0

Q45. Write a Java program to check whether a number is a perfect number.  
Input:  
Enter a number: 28

Expected Output:  
28 is a perfect number.

Q46. Write a Java program to check whether a number is an Armstrong number.  
Input:  
Enter a number: 153

Expected Output:  
153 is an Armstrong number.

Q47. Write a Java program to print all prime numbers between two intervals.  
Input:  
Enter start: 10  
Enter end: 20

Expected Output:  
Prime numbers: 11 13 17 19

Q48. Write a Java program to check whether a number is a palindrome.  
Input:  
Enter a number: 121

Expected Output:  
121 is a palindrome number.

Q49. Write a Java program to find the square root of a number.  
Input:  
Enter a number: 16

Expected Output:  
Square root = 4.0

Q50. Write a Java program to find the cube of a number.  
Input:  
Enter a number: 3

Expected Output:  
Cube = 27

Q51. Write a Java program to check if a year is a leap year.  
Input:  
Enter a year: 2020

Expected Output:  
2020 is a leap year.

Q52. Write a Java program to find the largest and smallest digits in a number.  
Input:  
Enter a number: 42593

Expected Output:  
Largest digit = 9  
Smallest digit = 2

Q53. Write a Java program to sort an array in ascending order.  
Input:  
Enter array elements: 5 3 8 6 1

Expected Output:  
Sorted array: 1 3 5 6 8

Q54. Write a Java program to calculate the factorial of a number using recursion.  
Input:  
Enter a number: 4

Expected Output:  
Factorial = 24

Q55. Write a Java program to calculate the product of digits of a number.  
Input:  
Enter a number: 234

Expected Output:  
Product of digits = 24

Q56. Write a Java program to count the number of uppercase and lowercase letters in a string.  
Input:  
Enter a string: JaVa

Expected Output:  
Uppercase letters: 2  
Lowercase letters: 2

Q57. Write a Java program to reverse an array.  
Input:  
Enter array elements: 1 2 3 4 5

Expected Output:  
Reversed array: 5 4 3 2 1

Q58. Write a Java program to calculate the sum of the main and secondary diagonal elements of a matrix.  
Input:  
Enter matrix elements:  
1 2 3  
4 5 6  
7 8 9

Expected Output:  
Main diagonal sum = 15  
Secondary diagonal sum = 15

Q59. Write a Java program to merge two arrays.  
Input:  
Array 1: 1 2 3  
Array 2: 4 5 6

Expected Output:  
Merged array: 1 2 3 4 5 6

Q60. Write a Java program to convert a character to uppercase.  
Input:  
Enter a character: a

Expected Output:  
Uppercase: A

Q61. Write a Java program to convert a string to uppercase.  
Input:  
Enter a string: hello

Expected Output:  
Uppercase: HELLO

Q62. Write a Java program to find the first and last digit of a number.  
Input:  
Enter a number: 4567

Expected Output:  
First digit = 4  
Last digit = 7

Q63. Write a Java program to find the GCD of two numbers.  
Input:  
Enter two numbers: 36 60

Expected Output:  
GCD = 12

Q64. Write a Java program to find the LCM of two numbers.  
Input:  
Enter two numbers: 5 7

Expected Output:  
LCM = 35

Q65. Write a Java program to print the Fibonacci series up to n terms.  
Input:  
Enter number of terms: 5

Expected Output:  
Fibonacci series: 0 1 1 2 3

Q66. Write a Java program to remove all spaces from a string.  
Input:  
Enter a string: Hello World

Expected Output:  
String without spaces: HelloWorld

Q67. Write a Java program to print all even numbers in a given range.  
Input:  
Enter start: 1  
Enter end: 10

Expected Output:  
Even numbers: 2 4 6 8 10

Q68. Write a Java program to print all odd numbers in a given range.  
Input:  
Enter start: 1  
Enter end: 10

Expected Output:  
Odd numbers: 1 3 5 7 9

Q69. Write a Java program to count the frequency of each character in a string.  
Input:  
Enter a string: java

Expected Output:  
a: 2  
j: 1  
v: 1

Q70. Write a Java program to reverse the digits of a number.  
Input:  
Enter a number: 1234

Expected Output:  
Reversed number: 4321

Q71. Write a Java program to find the maximum and minimum elements in an array.  
Input:  
Enter array elements: 2 8 5 3 9

Expected Output:  
Maximum: 9  
Minimum: 2

Q72. Write a Java program to convert a decimal number to binary.  
Input:  
Enter a decimal number: 10

Expected Output:  
Binary: 1010

Q73. Write a Java program to convert a binary number to decimal.  
Input:  
Enter a binary number: 1010

Expected Output:  
Decimal: 10

Q74. Write a Java program to calculate the power of a number.  
Input:  
Enter base: 2  
Enter exponent: 3

Expected Output:  
Result: 8

Q75. Write a Java program to find the sum of elements in an array.  
Input:  
Enter array elements: 1 2 3 4

Expected Output:  
Sum = 10

Q76. Write a Java program to find the average of numbers in an array.  
Input:  
Enter array elements: 5 10 15

Expected Output:  
Average = 10.0

Q77. Write a Java program to swap two variables without using a third variable.  
Input:  
Enter x: 5  
Enter y: 10

Expected Output:  
After swapping: x = 10, y = 5

Q78. Write a Java program to check whether a character is an alphabet or not.  
Input:  
Enter a character: A

Expected Output:  
The character is an alphabet.

Q79. Write a Java program to generate a multiplication table for a number.  
Input:  
Enter a number: 5

Expected Output:  
5 x 1 = 5  
5 x 2 = 10  
...  
5 x 10 = 50

Q80. Write a Java program to check if an array is sorted.  
Input:  
Enter array elements: 1 2 3 4 5

Expected Output:  
The array is sorted.

Q81. Write a Java program to find the second largest element in an array.  
Input:  
Enter array elements: 10 20 30

Expected Output:  
Second largest = 20

Q82. Write a Java program to count the number of digits in a number.  
Input:  
Enter a number: 12345

Expected Output:  
Number of digits = 5

Q83. Write a Java program to replace all vowels in a string with '*'.  
Input:  
Enter a string: Hello

Expected Output:  
H*ll*

Q84. Write a Java program to find the sum of the digits of a number.  
Input:  
Enter a number: 123

Expected Output:  
Sum of digits = 6

Q85. Write a Java program to count the number of words in a string.  
Input:  
Enter a string: Welcome to Java

Expected Output:  
Number of words = 3

Q86. Write a Java program to check if a number is divisible by both 3 and 5.  
Input:  
Enter a number: 15

Expected Output:  
15 is divisible by both 3 and 5.

Q87. Write a Java program to calculate the compound interest.  
Input:  
Enter principal: 1000  
Enter rate: 5  
Enter time: 2

Expected Output:  
Compound Interest = 1102.5

Q88. Write a Java program to calculate the area of a circle.  
Input:  
Enter radius: 7

Expected Output:  
Area = 153.93804

Q89. Write a Java program to check if a string contains only digits.  
Input:  
Enter a string: 12345

Expected Output:  
The string contains only digits.

Q90. Write a Java program to reverse a string using recursion.  
Input:  
Enter a string: Java

Expected Output:  
Reversed string: avaJ

Q91. Write a Java program to find the factorial of a number using recursion.  
Input:  
Enter a number: 5

Expected Output:  
Factorial = 120

Q92. Write a Java program to print all prime numbers in a given range.  
Input:  
Enter start: 10  
Enter end: 20

Expected Output:  
Prime numbers: 11 13 17 19

Q93. Write a Java program to find the length of the longest word in a string.  
Input:  
Enter a string: Java is amazing

Expected Output:  
Longest word length = 7

Q94. Write a Java program to print a right-angled triangle of stars.  
Input:  
Enter the number of rows: 4

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

Q95. Write a Java program to remove duplicate elements from an array.  
Input:  
Enter array elements: 1 2 2 3 4 4

Expected Output:  
Array after removing duplicates: 1 2 3 4

Q96. Write a Java program to check if a number is a palindrome.  
Input:  
Enter a number: 121

Expected Output:  
121 is a palindrome.

Q97. Write a Java program to check if a string is a palindrome.  
Input:  
Enter a string: madam

Expected Output:  
madam is a palindrome.

Q98. Write a Java program to calculate the sum of the diagonal elements of a matrix.  
Input:  
Enter matrix (3x3):  
1 2 3  
4 5 6  
7 8 9

Expected Output:  
Sum of diagonal elements = 15

Q99. Write a Java program to find the HCF and LCM of two numbers.  
Input:  
Enter two numbers: 12 18

Expected Output:  
HCF = 6  
LCM = 36

Q100. Write a Java program to rotate an array by one position to the right.  
Input:  
Enter array elements: 1 2 3 4 5

Expected Output:  
Rotated array: 5 1 2 3 4

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