This code sample contains methods to generate Prime numbers in a given range using Java.
import java.util.List;
public class PrimeNumber
{
public static void main(String[] args)
{
PrimeNumber pN = new PrimeNumber();
System.out.println("Is 73 a prime number -> " + pN.isPrime(73));
System.out.println("List of prime numbers up to 200 -> " + pN.getListOfPrimes(200));
}
public boolean isPrime(int n)
{
int k = (int) Math.sqrt(n);
for (int i = 2; i <= k; i++)
{
if (n % i == 0)
return false;
}
return true;
}
public List<Integer> getListOfPrimes(int end)
{
List<Integer> lstInt = new ArrayList<Integer>();
lstInt.add(1);
lstInt.add(2);
boolean flag = true;
for (int i = 3; i < end; i++)
{
flag = true;
int sqI = (int)Math.sqrt(i);
for (int j = 1; j < lstInt.size(); j++)
{
if (i % lstInt.get(j) == 0)
{
flag = false;
break;
}
if (sqI < lstInt.get(j))
{
break;
}
}
if (flag == true)
{
lstInt.add(i);
}
}
return lstInt;
}
}