[Question 1] ISC 2020 Computer Practical Paper Solved – Prime Adam Number

Click here to download the complete ISC 2020 Computer Science Paper 2 (Practical).

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Question:

A Prime-Adam integer is a positive integer (without leading zeros) which is a prirne as well as an Adam number.

Prime number : A number which has only two factors, i.e. 1 and the number itself.
Example: 2, 3, 5, 7 …etc.

Adam number: The square of a number and the square of its reverse are reverse to each other.
Exarnple: If n=13 and reverse of ‘n’ =31, then,
(13)²  = 169
(31)²  = 961 which is reverse of 169
thus 13, is an Adam number.

Accept two positive integers m and n, where m is less than n as user input. Display all Prime-Adam integers that are in the range between m and n (both inclusive) and output them along with the frequency, in the format given below:

Test your program with the following data and some random data:

Example 1

INPUT:

m=5
n=100

OUTPUT:

THE PRIME-ADAM INTEGERS ARE:
11 13 31
FREQUENCY OF PRIME-ADAM INTEGERS IS: 3

Example 2

INPUT:
m=100
n=200

OUTPUT:

THE PRIME-ADAM INTEGERS ARE:
101 103 113
FREQUENCY OF PRIME-ADAM INTEGERS IS: 3

Example 3

INPUT:
m=50
n=70

OUTPUT:

THE PRIME-ADAM INTEGERS ARE:
NIL
FREQUENCY OF PRIME-ADAM INTEGERS IS: 0

Example 4

INPUT:
m=700
n=450

OUTPUT: INVALID INPUT.

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Programming Code:

/**
  * The class ISC2020_Q1 inputs a lower and an upper range
  * and prints all the Prime-Adam numbers within that range
  * @author : www.guideforschool.com 
  * @Program Type : BlueJ Program - Java
  * @Question Year : ISC Practical 2020 Question 1 
  */
import java.util.*;
class ISC2020_Q1 //the main class
{
    boolean isPrime(int n) //to check for prime number
    {
        int c = 0;
        for(int i=1; i<=n; i++)
        {
            if(n%i == 0)
            {
                c++;
            }
        }
        if(c == 2)
            return true;
        else
            return false;
    }
    
    int reverseNum(int n) //to reverse a number
    {
        int r = 0, d = 0;
        while(n > 0)
        {
            d = n%10;
            r = r*10 + d;
            n = n/10;
        }
        return r;
    }
    
    boolean isAdam(int n) //to check for Adam number
    {
        int rev = reverseNum(n);
        int sqn = n*n;
        int sqr = rev * rev; //square of reverse
        int rsqn = reverseNum(sqn); //reverse of square
        if(rsqn == sqr)
            return true;
        else
            return false;
    }
    
    public static void main(String args[]) //the main method
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter the lower limit : ");
        int m = sc.nextInt();
        System.out.print("Enter the upper limit : ");
        int n = sc.nextInt();

        ISC2020_Q1 ob = new ISC2020_Q1();

        if(m<1 || n<1 || m>n) //checking for invalid input
        {
            System.out.println("INVALID INPUT");
        }
        else
        {
            int c = 0;
            System.out.println("THE PRIME-ADAM INTEGERS ARE:");
            for(int i=m; i<=n; i++)
            {
                if(ob.isPrime(i) && ob.isAdam(i)) //checking for prime-adam number
                {
                    c++;
                    System.out.print(i + "\t");
                }
            }
            if(c == 0)
            System.out.print("NIL");
            System.out.println("\nFREQUENCY OF PRIME-ADAM INTEGERS IS:" + c);
        }
    }
}

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Output:

Enter the lower limit : 100
Enter the upper limit : 200
THE PRIME-ADAM INTEGERS ARE:
101 103 113
FREQUENCY OF PRIME-ADAM INTEGERS IS:3