The implementation of sieve.d as presented at the bottom of the overview
page and in /dmd/src/d/example/sieve.d are inaccurate.

After making the following changes to the program:

bit[8191] flags; ==> bit[10] flags; // for testing only

between for loop and [printf ("\n%d primes", count);] insert:

  debug(print) {
    foreach(int ndx, bit val; flags) {
      if(flags[ndx]) {
        printf("%4d\t",ndx);
      }
    }
  }

the following inaccurate output were observed:

10 iterations
   0	   1	   2	   4	   5	   7	   8	
7 primes


New Implementation:
------sieve.d------
// Copyright (c) 2004 by Andrew Edwards
// I give up my rights and permit others to:
//      distribute
//      sell
//      give
//      modify
//      use
// I retain the right to be know as the author/owner

bit[8191] sieve;
void main()
{
  sieve[2..sieve.length] = true;
  int cnt;
  foreach(int ndx, bit val; sieve) {
    if(ndx == 0 || ndx == 1) continue;
    for(int j = ndx; j*ndx < sieve.length; j++)
      sieve[ndx*j] = false;
    if(val) count++;
  }
  printf("\n%d primes", cnt);
}

Correct Output: // tested with bit[10] sieve;
---------------
   2	   3	   5	   7	
4 primes

ciao Andrew

Andrew Edwards wrote:

> The implementation of sieve.d as presented at the bottom of the overview
> page and in /dmd/src/d/example/sieve.d are inaccurate.

Sorry! Make that:

  /dmd/samples/d/sieve.d

Andrew Edwards wrote:
>       sieve[ndx*j] = false;
>     if(val) count++;

correction: if(val) cnt++;

>   }
>   printf("\n%d primes", cnt);
> }