# Frequently Asked Algorithms & Java Programs

Below are most frequently asked algorithms and programs in interview to test interviewee programming and logical skill. These question can be asked with fresher and any senior level programmers to check hands on with the code or not.

1. Write a program to print alphabet using java loop
Output:
a b c d e f g h i j k l m n o p q r s t u v w x y z
a b c d e f g h i j k l m n o p q r s t u v w x y z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
2. Write a program to check odd or even number.
Input:  5
Output: Odd Number
3. Write a program to convert Fahrenheit to Celsius.
Input: 50
Output: 10.0
4. Write a java program to print fibonacci series without using recursion and using recursion.
Input: 12
Output: 0 1 1 2 3 5 8 13 21 34 55 89 144
5. Write a java program to check prime number.
Input: 42
Output: Not prime number
Input: 13
Output: Prime number
6. Write a java program to check palindrome number.
Input: 349
Output: Not palindrome number
Input: 1234321
Output: Palindrome number
7. Write a java program to print factorial of a number.
Input: 4
Output: 24
Input: 5
Output: 120
8. Write a java program to check Armstrong number.
Input: 153
Output: Armstrong number
Input: 22
Output: Not Armstrong number
9. Write a program to swap numbers without using third variable.
Input: 20 30
Output: 30 20
10. Write a program to reverse of number.
Input:    123456
Output: 654321
11. Write a program to find largest of three numbers.
Input: 10 30 40
Output: 40
12. Write a program to print Floyd triangle.
Input: 7
Output:

`1`
`2 3`
`4 5 6`
`7 8 9 10`
`11 12 13 14 15`
`16 17 18 19 20 21`
`22 23 24 25 26 27 28`

# Sorting Program

1. Write a java program to sort an array elements using bubble sort algorithm.
Input:    2 6 3 8 4 1 5 0
Output: 0 1 2 3 4 5 6 8
2. Write a java program to sort an array elements using selection sort algorithm.
Input:    2 6 3 8 4 1 5 0
Output: 0 1 2 3 4 5 6 8
3. Write a java program to sort an array elements using insertion sort algorithm.
Input:    2 6 3 8 4 1 5 0
Output: 0 1 2 3 4 5 6 8
4. Write a java program to sort an array elements using quick sort algorithm.
Input:    12 24 45 56 10 9 49 30 5 15
Output: 5 9 10 12 15 24 30 45 49 56
5. Write a java program to sort an array elements using heap sort algorithm.
Input:    2 6 3 8 4 1 5 0
Output: 0 1 2 3 4 5 6 8
6. Write a java program to sort an array elements using merge sort algorithm.
Input:    12 24 45 56 10 9 49 30 5 15
Output: 5 9 10 12 15 24 30 45 49 56
7. Write a java program to sort an array elements using shell sort algorithm.
Input:    2 6 3 8 4 1 5 0
Output: 0 1 2 3 4 5 6 8
8. Write a java program to sort an array elements using radix sort algorithm.
Input:   170 45 75 90 2 802 2 66
Output: 2 2 45 66 75 90 170 802
9. Write a java program to sort an array elements using bucket sort algorithm.
Input:   0.23 0.67 0.32 0.25 0.88 0.45 0.86 0.16 0.59 0.38 0.19 0.43 0.02
Output: 0.02 0.16 0.19 0.23 0.25 0.32 0.38 0.43 0.45 0.59 0.67 0.86 0.88
10. Write a java program to sort an array elements using counting sort algorithm.
Input:    2 6 3 2 8 4 8 1 5 3 1 4 0
Output: 0 1 1 2 2 3 3 4 4  5 6 8 8

# Fibonacci Series Java Program

“A fibonacci series is sequence of numbers, where each number is sum of the two preceding two numbers, Series initial two values are 1 , 1″

For Example : 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144………

# Fibonacci Series Program

Here is program to get Fibonacci series number on particular position and print series up to that point. In this program using recursion to generate Fibonacci numbers, Here put base condition to terminate recursion as when number reach to 1 or 2  and for rest of the case work recursively for current number and previous one and then add it.

```import java.util.HashMap;
import java.util.Map;

public class FibonacciSeriesExample {

private static Map series = new HashMap();

public static void main(String[] args) {

// Get the 12th fibonacci number from series
System.out.println("Fibonacci 12 the position element :" + fibonacci(12));

System.out.println("Print Complete Fibonacci Series :");
printFibonacci(series);
}

public static int fibonacci(int fibIndex) {

// set base element of fibonacci series
if (fibIndex == 1 || fibIndex == 2) {
series.put(1, 1);
series.put(2, 1);
}

// execute fibonacci recursively until fibIndex reach to 1
if (series.containsKey(fibIndex)) {
return series.get(fibIndex);
} else {
int answer = fibonacci(fibIndex - 1) + fibonacci(fibIndex - 2);
}
}

public static void printFibonacci(Map series) {

for (Map.Entry entry : series.entrySet()) {
System.out.println(entry.getValue());
}
}
}

```

## Output

``````
Fabonnici 12 the position element :144
Print Complete Fabonni Series :
1
1
2
3
5
8
13
21
34
55
89
144

``````