Prime number printer function, crashes when passed large enough numbers

I've got this piece of code that would print prime numbers up to the screen.

For example, printPrimes(500000) would fill the screen w开发者_高级运维ith all prime number's up to the 500000th one (which is 7368787).

Problem is, passing a larger number like 600000 or 1000000 would break the program.

Any ideas? Thanks in advance.

typedef enum {false, true} bool;

bool isPrime(long number, long primes[], long n) {
    int divisor, index;
    for (index = 0; index < n; ++index) {
        divisor = primes[index];
        if (divisor * divisor > number) {
            return true;
        } else if (number % divisor == 0) {
            return false;
        }
    }
    return 0;
}

void printPrimes(long n) {
    long primes[n];
    long odd, index;
    primes[0] = 2;
    odd = 1;
    index = 1;
    while (index < n) {
        odd += 2;
        if (isPrime(odd, primes, n)) {
            printf("%ld ", odd);
            primes[index] = odd;
            ++index;
        }
    }

}

---

Here:

long primes[n];

You are overflowing the stack if n is large enough (the stack is quite small). Try using malloc instead.

long *primes = malloc(sizeof(*primes) * n);