Kaprekar Number

Kaprekar Number

In mathematics, a non-negative integer is called a “Kaprekar number” if its square can be split into two parts that add up to the original number. For instance, 45 is a Kaprekar number, because 452 = 2025 and 20 + 25 = 45. Kaprekar numbers are named after D. R. Kaprekar.

Ex:

9, 45, 55, 99, 297, 703, 999, 2223, 2728, 4879, 4950, 5050, 5292, 7272, 7777

Java

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import java.util.*; public class Kaprekar {     public static void main()     {         Scanner sc = new Scanner(System.in);         int n, c=0, n2, sq, pow;         System.out.print("Enter the number: ");         n = sc.nextInt();       //Taking input         n2 = n;                 //Initialising copy         sq = n*n;               //Storing square         while(n>0)         {             n = n/10;           //Counting the number of digits             c++;         }         pow = (int)Math.pow(10, c); //Type casting         /*sq%pow gives the last c digits from the end of a square         where as sq/pow returns the starting digits*/         if(sq%pow + sq/pow == n2)                     System.out.println("The number is a Kaprekar number");         else             System.out.println("The number is not a Kaprekar number");     } } /*Type casting is the process of converting a value of a higher datatype to a value of lower data type. This results in a loss of data therefore is not automatically allowed by Java. ex: double x = 2.3; int y = x;  -->This will give a compile time error as double is a higher order data type as compared to int therefore: int y = (int)x; Order of data types: byte short char int long float double String */

Output