Added interview coding solutions - under #1

Author: darshanr27

Interview Coding Questions and Solutions/ArmstrongNumber.java

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+/*
+
+Q: Write a java program to check whether a given number is Armstrong number or not.
+Explainaion(case - sfor 3 digits number): An Armstrong number is a number whose sum of cubes of its digits is equal to the number itself.
+
+Example for Armstrong number(3 digit numbers): 153, 370, 371, 407.
+
+*/
+
+import java.util.Scanner;
+public class ArmstrongNumber {
+//Method to check if the given number is armstrong number or not
+	static void checkArmstrong(int num) {
+		int temp = num;
+		int sum = 0;
+		int digit;
+		while(num != 0) {
+			digit = num % 10;
+			sum += (digit * digit * digit);
+			num = num /10;
+		}
+		if(temp == sum)
+			System.out.println( temp + " is an Armstrong number");
+		else
+			System.out.println(temp + " is not an Armstrong number");
+	}
+//	Main method
+	public static void main(String[] args) {
+		Scanner scan = new Scanner(System.in);
+		System.out.println("Enter a number:");
+		int num = scan.nextInt();
+		checkArmstrong(num);
+	}
+}

Interview Coding Questions and Solutions/CheckLeapYear.java

@@ -2,6 +2,8 @@
 
 Q: Write a program to check if the year is leap or not.
 Exaplaintation: Leap year is a year which is divisible by 4 but not by 100, if the year is divisible by 400 then it is a leap year.
+Sample Input: 2016
+Sample Output: Leap Year
 
 */
 

Interview Coding Questions and Solutions/CheckPrime.java

@@ -2,6 +2,8 @@
 
 Q: Write a java program to check if the number is prime or not.
 Explaination: Prime number is a number which is divisible only by itself and 1.
+Sample Input: 5
+Sample Output: 5 is a prime number.
 
 */
 

Interview Coding Questions and Solutions/Factorial.java

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+/*
+
+Q: Write a java program to find the factorial of a number using recursion.
+Sample Input: 5
+Sample Output: 120
+
+*/ 
+
+import java.util.Scanner;
+public class Factorial {
+//	Method to find the recursion of the number using recursion
+	static int findFactorial(int n) {
+			if(n==0)
+				return 1;
+			else
+				return (n*findFactorial(n-1));
+	}
+//	Main method
+	public static void main(String[] args) {
+		Scanner scan = new Scanner(System.in);
+		System.out.println("Enter a number: ");
+		int num = scan.nextInt();
+		int fact = findFactorial(num);
+		System.out.println("Factorial of " + num + " is " + fact);
+		scan.close();
+	}
+}

Interview Coding Questions and Solutions/FibonacciSeries.java

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+/*
+
+Q: Write a java program to print the Fibonacci series upto n terms.
+Explanation: The Fibonacci series is the series of numbers: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ... The next number is found by adding up the two numbers before it.
+Sample Input: 5
+Sample Output: 0 1 1 2 3 5
+
+*/
+
+import java.util.Scanner;
+public class Demo {
+//	Method to print the Armstrong numbers in the given range
+	static void printFibonacciSeries(int limit) {
+		if(limit > 0) {
+			int first = 0, second = 1;
+			System.out.println("Fibonacci series upto " + limit + " are:");
+			System.out.print(first + " " + second);
+			int sum;
+			while(second <= limit) {
+				sum = first + second;
+				first = second;
+				second = sum;
+//				Condition to check the number to printed must be less than limit
+				if(sum <= limit)
+					System.out.print(" " + sum);
+			}
+		}
+		else {
+			System.out.println("Wrong input...! Try again");
+		}
+	}
+//	Main method
+	public static void main(String[] args) {
+		Scanner scan = new Scanner(System.in);
+		System.out.println("Enter the limit:");
+		int limit = scan.nextInt();
+		printFibonacciSeries(limit);
+		scan.close();
+	}
+}

Interview Coding Questions and Solutions/Palindrome.java

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+/*
+
+Q: Write a java program to check if a given string is a palindrome or not.
+
+Sample Input: malayalam
+Sample Output: Entered string is a palindrome.
+
+*/
+
+import java.util.Scanner;
+
+public class Palindrome {
+//Method to check if the given string is palindrome or not
+	static void checkPalindrome(String str) {
+		String revstr = "";
+//		Loop for reversing the string
+		for(int i = str.length()-1; i >=  0; i--) {
+			revstr += str.charAt(i);  
+		}
+//		Condition checking if the reversed string is equals to main string or not
+		if(str.equalsIgnoreCase(revstr)) {
+			System.out.println("Entered string is a palindrome");
+		}
+		else {
+			System.out.println("Entered string is not a palindrome");
+		}
+    }
+//	Main method
+	public static void main(String[] args) {
+		Scanner scan = new Scanner(System.in);
+		System.out.println("Enter a string: ");
+		String str = scan.next();
+		checkPalindrome(str);
+		scan.close();
+	}
+}

Interview Coding Questions and Solutions/PrintArmstrongNumbers.java

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+/*
+
+Q: Write a java program to print all the Armstrong numbers between given range.
+Explainaion: An Armstrong number is an integer such that the sum of the respective power of its digits is equal to the number itself.
+Sample Input: 1, 999.
+Sample Output: 1, 2, 3, 4, 5, 6, 7, 8, 9, 153, 370, 371, 407.
+
+*/
+
+import java.util.Scanner;
+
+public class PrintArmstrongNumbers {
+//Method to print the Armstrong number in the given range
+	static void printArmstrongNumber(int low, int high) {
+		System.out.println("Armstrong numbers in the range of " + low + " and " + high);
+//		Looping through the numbers in the given range
+		for(int num = low; num <= high; num++) {
+			int temp = num;
+			int digitCount = 0;
+			int digit;
+			int sum = 0;
+//			Looping for counting the number of digits
+			while(temp != 0) {
+				temp = temp / 10;
+				digitCount++;
+			}
+//			Resetting the temp
+			temp = num;
+//			Finding the sum of the respective power of the digits in the number
+			while(temp != 0) {
+				digit = temp % 10;
+				sum = (int) (sum + Math.pow(digit, digitCount));
+				temp = temp /10;
+			}
+//			Checking and printing only if the number is Armstrong number
+			if(num == sum)
+				System.out.print(num + " ");
+		}
+	}
+    
+//	Main method
+	public static void main(String[] args) {
+		Scanner scan = new Scanner(System.in);
+		System.out.println("Enter a starting number:");
+		int start = scan.nextInt();
+		System.out.println("Enter a ending number:");
+		int end = scan.nextInt();
+		printArmstrongNumber(start, end);
+		scan.close();
+	}
+}

Interview Coding Questions and Solutions/ReverseNumber.java

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+/*
+
+Q: Write a java program to reverse a number.
+
+Sample Input 1: 12345
+Sample Output 1: 54321
+
+Sample Input 3: -12345
+Sample Output 3: -54321
+
+*/
+
+import java.util.Scanner;
+
+public class ReverseNumber {
+//Method to reverse the given number
+	static void reverseNumber(int num) {
+		int digit;
+		int rev = 0;
+		while(num != 0) {
+			digit = num%10;
+			rev = rev*10 + digit;
+			num = num/10;
+		}
+		System.out.println("Reversed number:");
+		System.out.println(rev);
+    }
+//	Main method
+	public static void main(String[] args) {
+		Scanner scan = new Scanner(System.in);
+		System.out.println("Enter a number: ");
+		int n = scan.nextInt();
+		reverseNumber(n);
+		scan.close();
+	}
+}

Interview Coding Questions and Solutions/SumOfDigits.java

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+/*
+
+Q: Write a java program to find the sum of digits of a number.
+Sample Input: 12345
+Sample Output: 15
+
+*/
+
+import java.util.Scanner;
+public class SumOfDigits {
+//Method to find the sum of the digits of the number
+	static void findDigitSum(int num) {
+		int digit, sum = 0;
+		while(num > 0) {
+			digit = num%10;
+			sum += digit;
+			num = num/10;
+		}
+		System.out.println(sum);
+	}
+//	Main method
+	public static void main(String[] args) {
+		Scanner scan = new Scanner(System.in);
+		System.out.println("Enter a number: ");
+		int n = scan.nextInt();
+		findDigitSum(n);
+		scan.close();
+	}
+}