int prIsPrime(VMGlobals *g, int numArgsPushed)
{
PyrSlot *a;
int n, p, sqrtn, i;
a = g->sp;
n = slotRawInt(a);
SetNil(a);
if (n <= 2) {
if (n == 2) { SetTrue(a); }
else { SetFalse(a); }
} else if (n <= nthPrime(NUMPRIMES-1)) {
// do a search of the primes table
i = findPrime(n);
if (i >= 0) { SetTrue(a); }
else { SetFalse(a); }
} else {
#ifdef SC_WIN32
sqrtn = (int)sqrt(static_cast<double>(n));
#else
sqrtn = (int)sqrt(n);
#endif
for (i=0; i<NUMPRIMES; ++i) {
p = nthPrime(i);
if (n % p == 0) { SetFalse(a); break; }
if (p >= sqrtn) { SetTrue(a); break; }
}
}
return errNone;
}
int main(int argc, char *argv[])
{
int *primes = NULL;
int nthPrimeNum = 0;
int thePrime = 0;
int i = 0;
if (argc != 2) return 0;
nthPrimeNum = atoi(argv[1]);
primes = malloc(sizeof(*primes) * nthPrimeNum);
*primes = 2;
thePrime = findPrime(nthPrimeNum, primes);
printf("\nthe %dth prime is %d\n", nthPrimeNum, thePrime);
for (i=0; i<nthPrimeNum; i++) {
printf("%d, ", primes[i]);
}
printf("\n");
free(primes); //XXX: will this leak memory?
return 0;
}
int main(){
int N,count = 0;
scanf("%d", &N);
findPrime(N);
for(int i = 1; i < pNum; ++i){
if(prime[i] - prime[i-1] == 2){
count++;
}
}
printf("%d\n",count);
return 0;
}
void theSieve(int n) {
// start with 2
// cross out all multiples of 2
// then move to 3
// cross out all mutliple of 3
// then continue repeating
int *numSet = malloc(n*sizeof(int));
// populate array
int i = 0;
int p = 2;
while (i <= n-2) {
numSet[i] = p;
i++;
p++;
}
i = 0;
int count = 0;
int numOfPrimes = 0;
while (i <= n-2) {
if (numSet[i] != -1 && findPrime(numSet[i]) == TRUE) {
numOfPrimes++;
count = 1;
while (count <= n-2) {
if (numSet[i] * count == numSet[count]) {
numSet[count] = -1;
}
count++;
}
}
i++;
}
printf("%d\n", numOfPrimes );
free(numSet);
}
int prIndexOfPrime(VMGlobals *g, int numArgsPushed)
{
PyrSlot *a;
int n, p;
a = g->sp;
n = slotRawInt(a);
if (n <= 2) {
if (n == 2) { SetInt(a, 0); }
else { SetNil(a); }
} else if (n <= nthPrime(NUMPRIMES-1)) {
p = findPrime(n);
if (p < 0) {
SetNil(a);
} else {
SetInt(a, p);
}
} else {
SetNil(a);
}
return errNone;
}
int main(int argc, const char * argv[]) {
findPrime(atoi(argv[1]));
return 0;
}
