Page 565 - ComputerScience_Class_11
P. 565
Program 2 This class is designed to accept a positive integer in binary form and display whether it is a
Pernicious number or not. A Pernicious number is a binary number that has a minimum of
two digits and the number of 1's in it is a prime number.
Examples:
• 101 is a pernicious number because the number of 1's in 101 is 2 and 2 is a prime number.
• 101010 is a pernicious number because the number of 1's in 101010 is 3 and 3 is a prime
number.
• 1111 is not a pernicious number because the number of 1's in 1111 is 4 and 4 is not a
prime number.
1 import java.util.Scanner;
2 public class Perni
3 {
4 public static void main(String args[])
5 {
6 String num;
7 Scanner scanner = new Scanner(System.in);
8
9 System.out.print("Enter a binary number: ");
10 num = scanner.nextLine();
11
12 int count = 0;
13 int length = num.length();
14 for (int i = 0; i < length; i++)
15 {
16 if (num.charAt(i) == '1')
17 {
18 count++;
19 }
20 }
21
22 boolean isPrime = true;
23 if (count <= 1)
24 {
25 isPrime = false;
26 }
27 else
Internal Assessment 563
