Automorphic Number (#2343)

Maths/AutomorphicNumber.java

@@ -0,0 +1,63 @@
+/**
+ * A number is said to be an Automorphic, if it is present in the last digit(s) of its square.
+ * Example- Let the number be 25, its square is 625.
+ *          Since, 25(The input number) is present in the last two digits of its square(625),
+ *          it is an Automorphic Number.
+ */
+import java.io.*;
+
+public class AutomorphicNumber
+{
+    //returns True if the number is a Automorphic number and False if it is not an Automorphic number
+    public static boolean isAutomorphic(int n)
+    {
+        int m, c, r, p, k; c = 0;
+        /** m = Temporary variable to store a copy of the number entered by the user.
+         * n = The number entered by the user
+         * c = Count the digits of the number entered by user.
+         * p = To calculate the square of the number.
+         * k = Support variable to count the digits of the number
+         */
+        double s;
+        m = n;
+        p = m * m; //Calculating square of the number
+        do
+        {
+            k = n / 10;
+            c = c + 1; //Counting the digits of the number entered by user.
+            n = k;
+        }
+        while(n != 0);
+        s = Math.pow(10, c); 
+        r = p %(int)s;
+        if(m == r) //Checking if the original number entered is present at the end of the square
+        {
+            return true;
+        }
+        else
+        {
+            return false;
+        }
+    }
+
+    /** Method to check if number is Automorphic Number or Not
+     *  1) Input  - Enter a Number: 25
+     *     Output - It is an Automorphic Number.
+     *  2) Input  - Enter a Number: 7
+     *     Output - It is not an Automorphic Number.
+     */
+    public static void main(String args[]) throws IOException
+    {
+        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
+        System.out.println("Enter a Number: ");
+        int n=Integer.parseInt(br.readLine());
+        if(isAutomorphic(n))
+        {
+            System.out.println("It is an Automorphic Number.");
+        }
+        else
+        {
+            System.out.println("It is not an Automorphic Number.");
+        }
+    }
+}