Question

Code to be written in Java

public static boolean isPrime(int n)

Checks whether the parameter integer n is a prime number. For this lab, it is sufficient to use the primality test algorithm that simply loops through all potential integer factors up to the square root of n and stops as soon as it finds one factor. (If an integer has any nontrivial factors, at least one of these factors has to be less than or equal to its square root, so it is pointless to look for any such factors past that point if you haven't already found some.)

Answer 1

Below is your java code :)

import java.util.Scanner; // for taking input from user

// function to check if the number is prime or not
public class IsPrime {

   public static boolean isPrime(int n)
   {
       // if number is smaller than 1 return false
       if(n <= 1)
           return false;
       // check each number till square root of given number
       for(int i=2;i<Math.sqrt(n);i++)
           if(n%i == 0)
               // if number is divisible by any number return false
               return false;
       // else return true as number is prime
       return true;
   }
   public static void main(String[] args) {
       Scanner in = new Scanner(System.in);
       int choice=1; // variable to run the while loop
       int number=0; // variable to hold the number of the user
       boolean prime = false; // variable to hold the return value of isPrime function
       do
       {
           System.out.print("Enter a number: ");
           number = in.nextInt();
           prime = isPrime(number);
           if(prime == true)
               System.out.println(number+" is Prime.");
           else
               System.out.println(number+" is not Prime.");
           System.out.println("\nDo you want to continue \n1. Yes \n2. No");
           choice = in.nextInt();
           System.out.println("\n");
       }while(choice != 2);

   }

}

Sample output: