Optimizing prime numbers code?

Question

I wrote this code to show the primes between 1 and 100. The only condition is to do not use functions, whole code should be inline. I would ask if I can improve (optimize) it mu

Answer 1

/*** Return an array of primes from 2 to n. ***/
int[] function nPrimes(int n) {
   int primes[];  //memory allocation may be necessary depending upon language.
   int p = 0;
   bool prime;
   for (int i = 2; i <= n; i++) {
       prime = true;
       //use (j <= (int)sqrt(i)) instead of (j < i) for cost savings.
       for (int j = 2; j <= (int)sqrt(i); j++)  {
           if (i % j == 0) {
               prime = false;
               break;
           }
       }
       if (prime) {
           primes[p++] = i;
       }    
   }
   return primes;
}