Answer SL39

prime: 2
prime: 3
prime: 5

Comments: Memory for primes and for index is allocated just once, when the program first starts running. Both are initialized at that time. Each time nextPrime() is called, the index is incremented, and the next value from the array is returned. The index retains its value across calls so that each call returns the next value.

int nextPrime()
{
  static int primes[] = { 2, 3, 5, 7, 11, 13, 17, 23 };
  static int index = -1;
  index++ ;
  return primes[index];
}

(The code, as written, is not very safe. It will start returning strange values when index goes beyond the end of the array.)