ICSE 2018 Pronic Number Question 5

Write a program to input a positive number and check and print whether it is a Pronic number or not. (Pronic number is a number which can be written as product of two consecutive integers)
Example:
12 = 3 x 4
42 = 6 x 7
20 = 4 x 5

ENTER A POSITIVE INTEGER:

 class PronicNumber:

    def pronicRepresentation(self):

        print(self.__number," is a Pronic Number. ",self.__number," = ",self.__index," x ",(self.__index+1))

    def isPronic(self):

        i = 1

        while (i*(i+1) <= self.__number):

            if(i*(i+1) == self.__number):

                self.__flag = True

                self.__index = i

                break

            i +=1

        return(self.__flag)

    def __init__(self,n):

        self.__number = n

    __number = 0

    __index = -1

    __flag = False

n = int(input("Enter a positive integer."))

obj = PronicNumber(n)

if(obj.isPronic()):

    obj.pronicRepresentation()

else:

    print(n," is not a Pronic Number.")

 import java.util.Scanner;

public class ICSEJava {

    public static void main(String[] args) {

        int n;

        Scanner in = new Scanner(System.in);

        System.out.println("Enter a positive integer:");

        n = in.nextInt();

        PronicNumber obj = new PronicNumber(n);

        if(obj.isPronic())

            obj.pronicRepresentation();

        else

            System.out.println(n+" is not a Pronic Number");

        in.close();

    }

}

class PronicNumber {

    public void pronicRepresentation() {

        System.out.println(number+" is a Pronic Number. "+number+" = "+index+" x "+(index+1));        

    }

    public boolean isPronic() {

        int i = 1;

        while(i*(i+1) <= number){

            if(i*(i+1) == number) {

                flag = true;

                index = i;

                break;

            }

            i++;

        }

        return(flag);

    }

    PronicNumber(int n){

        number = n;

        flag = false;

        index = -1;

    }

    int number;

    int index;

    boolean flag;

}