#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define MAX 15485863
#define LMT 1000000
unsigned flag[MAX>>6];
#define ifc(n) (flag[n>>6]&(1<<((n>>1)&31)))
#define isc(n) (flag[n>>6]|=(1<<((n>>1)&31)))
void sieve() {
unsigned i, j, k;
for(i=3; i<LMT; i+=2)
if(!ifc(i))
for(j=i*i, k=i<<1; j<MAX; j+=k)
isc(j);
}
int main(int argc, char *argv[])
{
long starttime = clock();
sieve();
starttime = clock() - starttime;
printf("Time: %2d ms. Size: %d", starttime, MAX>>6);
}
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