package others;
import lessones01.LinkedList;
public class PrimeGetter{
private static LinkedList<Integer> primes = new LinkedList<Integer>();
public static int get(int arg_num){
for(int i = primes.size()-1;i<arg_num;i++){add();}
return primes.get(arg_num);
}
private static void add(){
int size = primes.size();
if(size == 0){
primes.add(2);
}else if(size == 1){
primes.add(3);
}else{
for(int x = primes.get(size-1)+2;;x+=2){
boolean isPrime = true;
int floatPrime;
int z = (int)Math.sqrt(x);
for(int i=1;i<size;i++){
if(x%(floatPrime = primes.get(i)) == 0){
isPrime = false;
break;
}
if(z<floatPrime){break;}
}
if(isPrime){
primes.add(x);
return;
}
}
}
}
public static boolean isPrime(int arg_num){
int i = 0;
for(;arg_num>get(i);i++){}
return arg_num == primes.get(i);
}
}