Add Krishnamurthy Number (hacktoberfest) (#2349)

This is a program to check if a number is a Krishnamurthy number or not.
A number is a Krishnamurthy number if the sum of the factorials of the digits of the number is equal to the number itself.
For example, 1, 2 and 145 are Krishnamurthy numbers.

Maths/KrishnamurthyNumber.java

@@ -0,0 +1,70 @@
+//package Maths;
+
+/* This is a program to check if a number is a Krishnamurthy number or not.
+A number is a Krishnamurthy number if the sum of the factorials of the digits of the number is equal to the number itself.
+For example, 1, 2 and 145 are Krishnamurthy numbers.
+Krishnamurthy number is also referred to as a Strong number.
+*/
+
+import java.io.*;
+
+public class KrishnamurthyNumber
+{
+	//returns True if the number is a Krishnamurthy number and False if it is not.
+	public static boolean isKMurthy(int n)
+	{
+		//initialising the variable s that will store the sum of the factorials of the digits to 0
+		int s=0;
+		//storing the number n in a temporary variable tmp
+		int tmp=n;
+
+		//Krishnamurthy numbers are positive
+		if(n<=0)
+		{
+			return false;
+		}
+
+		//checking if the number is a Krishnamurthy number
+		else
+		{
+			while(n!=0)
+			{
+				//initialising the variable fact that will store the factorials of the digits
+				int fact=1;
+				//computing factorial of each digit
+				for (int i=1;i<=n%10;i++)
+				{
+					fact=fact*i;
+				}
+				//computing the sum of the factorials
+				s=s+fact;
+				//discarding the digit for which factorial has been calculated
+				n=n/10;
+			}
+
+			//evaluating if sum of the factorials of the digits equals the number itself
+			if(tmp==s)
+			{
+				return true;
+			}
+			else
+			{
+				return false;
+			}
+		}
+	}
+	public static void main(String args[]) throws IOException
+	{
+		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
+		System.out.println("Enter a number to check if it is a Krishnamurthy number: ");
+		int n=Integer.parseInt(br.readLine());
+		if(isKMurthy(n))
+		{
+			System.out.println(n+" is a Krishnamurthy number.");
+		}
+		else
+		{
+			System.out.println(n+" is NOT a Krishnamurthy number.");
+		}
+	}
+}