# [racket] How to verify prime numbers.

 From: Rodolfo Carvalho (rhcarvalho at gmail.com) Date: Thu Jul 14 02:04:07 EDT 2011 Previous message: [racket] How to verify prime numbers. Next message: [racket] How to verify prime numbers. Messages sorted by: [date] [thread] [subject] [author]

```Hello,

Well, no one here is gonna do your homework!
You could start showing what you've done so far and asking more specific
doubts.

We are not code translation robots...

[]'s

Rodolfo Carvalho

2011/7/14 飞刀 <fly3ds at qq.com>

> Hello everyone,
>
> I want a program to verify prime numbers which can be runned in mzscheme.
> The following is C source.  I don't konwn how to convert it to lisp.
>
> Thanks.
>
> #include <stdio.h>
> #include <time.h>
> #include <math.h>
> #include <string.h>
> #include <stdlib.h>
>
> #define E6 1000000
>
> char table[E6];
> int num = 0;
> //int prime[E8];
>
> void cal_table()
> {
> int j, k;
> time_t t1, t2;
> t1 = time(NULL);
> memset(table, 1, E6);
> for (j = 2 ; j < E6; j++) {
> if ( table[j] ) {
> num++;
> for ( k = j + j; k < E6; k += j )
> {
> table[k] = 0;
> }
> }
> }
> t2 = time(NULL);
> printf("Totaly %d primes until E6, cost %d time_t.\n", num, t2 - t1);
> }
>
> /*
> void init_prime()
> {
> int i;
> num = 0;
> printf("Init prime start...");
> for (i = 2; i < 2*E9; i++) {
> if (table[i])
> prime[num++] = i;
> }
> printf("Init prime finished...");
> }
> */
>
> int main()
> {
> int i;
> cal_table();
> //init_prime();
> return 0;
> }
>
>
> _________________________________________________