Using SDL(Simple DirectMedia Layer) Libraries in Ubuntu - c

Question

i'm trying to include all SDL libraries that i have already installed and exist in '/usr/include/SDL' this directory contains all .h files
#include <SDL/SDL.h>
#include <stdio.h>
#include <stdlib.h>
int main ()
{
SDL_Surface *screen=NULL ;
SDL_Init (SDL_INIT_VIDEO);
if (SDL_Init(SDL_INIT_VIDEO !=0))
{
printf("erreur");
return 1 ;
}
screen=SDL_SetVideoMode (400,400,32,SDL_HWSURFACE | SDL_DOUBLEBUF);
if (screen== NULL)
{
printf("Unable to set video mode : %s \n",SDL_GetError() );
return 1;
}
SDL_Flip (screen);
SDL_Quit ();
return 0;
}
when i compile code above that exists in main.c in terminal using this command:
gcc main.c -o program -LSDL
i get this :
axemaster#ubuntu:~/Desktop/stackoverflow$ gcc main.c -o program -LSDL
/tmp/ccMx1per.o: In function `main':
main.c:(.text+0x16): undefined reference to `SDL_Init'
main.c:(.text+0x20): undefined reference to `SDL_Init'
main.c:(.text+0x53): undefined reference to `SDL_SetVideoMode'
main.c:(.text+0x63): undefined reference to `SDL_GetError'
main.c:(.text+0x88): undefined reference to `SDL_Flip'
main.c:(.text+0x8d): undefined reference to `SDL_Quit'
collect2: error: ld returned 1 exit status
How can i solve this ?