/* // Project Euler // Problem #: 7 // By: TheEngineer // Date: 09/12/10 */ public class Euler7 { public static void main(String args[]) { int[] primes = new int[10002]; int tmp = 0; for ( int i = 2; i < 10000000; i++ ) { // Search for primes up to the number 1,000,000 int j = 0; // primes[j] goes from places 0 to 10,001. while ( j < 10002 ) { if ( isPrime(i) && i > tmp ) { primes[j] = i; tmp = i; j++; } break; } } System.out.println(primes[10001]); // Print the 10,001st prime number } public static boolean isPrime( int x ) { // Checks to see if a number is prime for ( int i = 2; i <= x / 2; i++ ) { // i starts at 2, while i < half of x (int i from main), incriment i by one each time we loop if ( x % i == 0 ) { // if x is divisible by any number that is <= half of it, then x is NOT prime return false; } } return true; // If x isn't divisible by any number other than itself and one, then x IS prime } }

I tried commenting this time, hope that helps. The reason I decided to use a while loop, incrementing j by 1 each time, was because I thought this would save a lot of time. Rather than looping through every number between 2 and 1,000,000 over 10,000 times. I could be wrong but this makes sense to me.

Tell me why I am wrong please.