Question

Code in Java to be typed in Eclipse.

list. Then create another ArrayList L2, with all the prime numbers in the list L1. Use an enhanced for-loop instead of an ordinary for-loop in your program

Answer 1

//RandomList.java
import java.util.ArrayList;
import java.util.Random;
import java.util.Scanner;

public class RandomList {

   public static void main(String[] args) {
      
       Scanner s = new Scanner(System.in); //Scanner object to get input N from user
       System.out.println("Enter number of random Integers to generate: ");
       int n = s.nextInt();
       //Creating ArrayLists
       ArrayList<Integer> L1 = new ArrayList<Integer>();
       ArrayList<Integer> L2 = new ArrayList<Integer>();
       //Creating an object to generate random numbers
       Random r = new Random();
       for(int i=0; i<n; i++)   // This will add N random integers to the list L1.
       {
           L1.add(r.nextInt(1000));       //r.nextInt(1000) will generate random integers between 0 and 1000, and add them to list L1
       }
       //using enhanced for loop to add prime numbers from L1 to L2
       for(int num : L1)
       {
           int i = 2;
           boolean prime = true; // a flag to check for prime
           //If the generated random numbers are 1 or 2, adding 1 and 2 to the prime numbers list L2
           if(num==1)
               L2.add(num);
           else if(num==2)
               L2.add(num);
           else
           {
               while(i<=num/2)  
               {
                   if(num%i == 0)        //checking if the number is divisible, i.e. if it is a prime number or not
                   {
                       prime = false;
                       break;
                   }
                   i++;
               }
               if(prime)
               {
                   L2.add(num);   //add the number to List L2 if it is a prime number;
               }
           }
       }
       System.out.println("List L1");
       System.out.println(L1);
       System.out.println("List L2 Prime");
       System.out.println(L2);
   }
}