# prime number program in C

Discussion in 'C' started by matthughesfan1980, May 8, 2007.

1. ### matthughesfan1980New Member

Joined:
May 8, 2007
Messages:
2
0
Trophy Points:
0
Hello all i am so new and trying to learn while i serve.
I am supposed to write a program that prints out the first n primes, where n is input by the user. I am supposed to write my program in its own directory in three files: primes.h, main.c, and is_prime.c
This is what the output is supposed to look like:

PRIMES WILL BE PRINTED.

How many do you want to see? 3000

Code:
1:      2
2:      3
3:      5
4:      7
5:     11
.....
25:     97
26:    101
.......
2998:  27431
2999:  27437
3000:  27449
........
10000:
This is the files that I have so far:
is_primes.h:
Code:
#include <stdio.h>
#include <stdlib.h>

int   is_prime(int n);

is_prime.c
Code:
#include "primes.h"

int is_prime(int n)
{
int   k, limit;

if (n == 2)
return 1;
if (n % 2 == 0)
return 0;
limit = n / 2;
for (k = 3; k <= limit; k += 2)
if (n % k == 0)
return 0;
return 1;
}

main.c
Code:
#include "primes.h"

int main(void)
{
printf("PRIMES WILL BE PRINTED\n\n");
printf("How many do you want to see?     \n");
scanf("%5d",
return 0;
}
I dont know how to link it to the files and what to fill in the main.c file to make it work. Some guidance would be great

Last edited by a moderator: May 8, 2007

Joined:
Jul 12, 2004
Messages:
15,296
366
Trophy Points:
83
Please use the Code Block when you have code in the posts
Give an appropriate Title. Your title said Visual Basic and you gave the code of C/C++. I edited it for you.
You just happen to post in Introduce yourself and I moved to C-C++ for better response.
Also you had the same post as an article of C-C++

Last edited: May 8, 2007

Joined:
Apr 4, 2005
Messages:
1,646
86
Trophy Points:
0
Occupation:
Programmer
Location:
Kolkata, India
4. ### DaWeiNew Member

Joined:
Dec 6, 2006
Messages:
835
5
Trophy Points:
0
Occupation:
Semi-retired EE
Location:
Texan now in Central NY

5. ### aVagueNew Member

Joined:
May 2, 2007
Messages:
34
0
Trophy Points:
0
Occupation:
forex
You need to compile them together or what?

if yes, one way is to copy "is_primes.h" and "is_prime.c" in libraly of Builder or visual studio(if you have)
to "include" - you ll find it , where your program(builder/studio) is installed. if you cant (so you have linux and "vim"), then you collect ALL this programs in compiling directory and write, as usual , "gcc..."