The Array Method (Sieve of Eratosthenes) in C

#include 
#include 
#include 
#include 

typedef  unsigned long long bignum;

void printPrime(bignum bn)
 {
 static char buf[1000];

 sprintf(buf, "%ull", bn);
 buf[strlen(buf) - 2] = '\0';
 printf("%s\n", buf);
 }

void findPrimes(bignum topCandidate)
 {
 char * array = malloc(sizeof(unsigned char) * (topCandidate + 1));
 assert(array != NULL);

 /* SET ALL BUT 0 AND 1 TO PRIME STATUS */
 int ss;
 for(ss = 0; ss <= topCandidate+1; ss++)
  *(array + ss) = 1;
 array[0] = 0;
 array[1] = 0;

 /* MARK ALL THE NON-PRIMES */
 bignum thisFactor = 2;
 bignum lastSquare = 0;
 bignum thisSquare = 0;
 while(thisFactor * thisFactor <= topCandidate)
  {
  /* MARK THE MULTIPLES OF THIS FACTOR */
  bignum mark = thisFactor + thisFactor;
  while(mark <= topCandidate)
   {
   *(array + mark) = 0;
   mark += thisFactor;
   }

  /* PRINT THE PROVEN PRIMES SO FAR */
  thisSquare = thisFactor * thisFactor;
  for(;lastSquare < thisSquare; lastSquare++)
   {
   if(*(array + lastSquare)) printPrime(lastSquare);
   }

  /* SET thisFactor TO NEXT PRIME */
  thisFactor++;
  while(*(array+thisFactor) == 0) thisFactor++;
  assert(thisFactor <= topCandidate);
  }

 /* PRINT THE REMAINING PRIMES */
 for(;lastSquare <= topCandidate; lastSquare++)
  {
  if(*(array + lastSquare)) printPrime(lastSquare);
  }
 free(array);
 }

int main(int argc, char *argv[])
 {
 bignum topCandidate = 1000;
 if(argc > 1)
  topCandidate = atoll(argv[1]);
 findPrimes(topCandidate);
 return 0;
 }