
how to find prime numbers in a given range which are palindromes??

Hi Friend,
Try the following code:
import java.util.*;
public class PrimeAndPalindrome {
static final int MAXNUMBER=200;
private int number;
private ArrayList<Integer> list = new ArrayList<Integer>();
public PrimeAndPalindrome(int maxNum){
number=maxNum;
}
ArrayList<Integer> isPalindrome(){
for (int i=10; i<=number; i++){
Integer in=new Integer(i);
String number=in.toString();
int index1=0;
int index2=number.length()-1;
char x=number.charAt(index1);
char y=number.charAt(index2);
while (index2-index1>=0){
if(x!=y)
break;
if (index2-index1==0 || index2-index1==1)
list.add(i);
index1++;
index2--;
x=number.charAt(index1);
y=number.charAt(index2);
}
}
return list;
}
static boolean isPrime(int number){
boolean isPrime=false;
int i=(int) Math.ceil(Math.sqrt(number));
while (i>1){
if ((number!=i) && (number%i==0)){
isPrime=false;
break;
}
else if (!isPrime)
isPrime=true;
--i;
}
return isPrime;
}
public static void main(String[] args) {
ArrayList<Integer> palindromes=new ArrayList<Integer>();
PrimeAndPalindrome pp=new PrimeAndPalindrome(MAXNUMBER);
palindromes=pp.isPalindrome();
Iterator<Integer> iter=palindromes.iterator();
while (iter.hasNext()){
int current=iter.next();
if (isPrime(current))
System.out.println(current);
}
}
}
Thanks

thnks buddy..but can u clearify what that ArrayList exactly doing?
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