C

For this algorithm, the languages C, C++, C# and Java are essentially indistinguishable from one another. They are not identical -- there are slight differences. Note the different I/O functions used for C and C++.

This program compiles and runs on Linux (Red Hat Enterprise) gcc.


//////////////////////////////////////////////////////////

// Name: Peter M. Maurer

// Program: Sieve of Eratosthenes

// Due: Never

// Language: C

//////////////////////////////////////////////////////////


#include <stdio.h>



int main()


{


// define the sieve data structure


int Candidates[1000];


int i;


for (i=0 ; i<1000 ; i++)


{


// everything is potentially prime until proven otherwise


Candidates[i] = 1;


}


// Neither 1 nor 0 is prime, so flag them off


Candidates[0] = 0;


Candidates[1] = 0;


// start the sieve with the integer 0


i = 0;


while (i<1000)


{


// advance to the next un-crossed out number.


// this number must be a prime


while (i<1000 && Candidates[i] == 0)


{


i++;


}


// insure against running off the end of the data structure


if (i<1000)


{


// cross out all multiples of the prime, starting with 2*p.


int j;


for (j=2 ; j*i < 1000 ; j++)


{


Candidates[j*i] = 0;


}


// advance to the next candidate


i++;


}


}


// all uncrossed-out numbers are prime (and only those numbers)


// print all primes


for (i=0 ; i<1000 ; i++)


{


if (Candidates[i] != 0)


{


fprintf(stderr,"%d is prime\n",i);


}


}


return 0;


}

Click Here for the actual code.