This is an intro Java programming class. A positive integer is prime if it\'s di

Question

This is an intro Java programming class. A positive integer is prime if it's divisible by only 1 and itself. For example, 2, 3, 5 and 7 are prime, but 4, 6, 8 and 9 are not. The number 1, by definition, is not prime.

a.) Write a method that determines whether a number is prime.

b.) Use this method in an application that determines and displays all the prime numbers less than 10,000. How many numbers up to 10,000 do you have to test to ensure that you've found all the primes?

c.) Initially, you might think that n/2 is the upper limit for which you must test to see whether a number n is prime, but you need to only go as high as the square root of n. Re-write the program, and run it both ways.

please ensure your answer/code is error free and add comments on your steps so i can read it.

Explanation / Answer

a)public static boolean isPrime(int n)   
{
for(int i = 2; i<=n/2; i++)
{                                         
if(n%i== 0)  
return false;
else
return true;
}
}

b)

public class PrimeNumbers {

    public static void main(String[] args) {
      
        System.out.println("List of prime numbers");
        for (int i = 2; i <= 10000; i++) {
            if (isPrime(i)) {
                System.out.println(i);
            }
        }
    }

c)

public static boolean isPrime(int n)
{
int sqrt = (int) Math.sqrt(n) + 1;
for (int i = 2; i < sqrt; i++)
{ if (n % i == 0) {
return false;
}
}
return true;
}

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