Application client seveur si simple en c et sous linux

Bonjour,
je voulais realise en programmation sockets une petite application de client serveur ,
sous linux j ai les 2 codes , un pour client , et l autre pour serveur , bon sous le terminal j ai pu compiler le code serveur , mais pour le code client ca marche pas , je recois plusieurs warning , et le code ne se compile pas :( , est ce que vous pouvez m aider a corriger les erreurs dans ce programme s il vous plait /
cette petite application est base sur le language C
le voila

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

void error(char *msg)
{
perror(msg);
exit(0);
}

int main(int argc, char *argv[])
{
int sockfd, portno, n;
struct sockaddr_in serv_addr;
struct hostent *server;

char buffer[256];

if (argc < 3)
{
fprintf(stderr,"usage %s hostname port\n", argv[0]);
exit(0);
}

portno = atoi(argv[2]);

sockfd = socket(AF_INET, SOCK_STREAM, 0);

if (sockfd < 0 )
{
              error("ERROR opening socket");
}

server = gethostbyname ( argv[1]);

if( server == NULL ) 
{
          fprintf(stderr ,"ERROR , no such host\n");
          exit(0);
}



bzero((char *) &serv_addr ,sizeof((serv_addr));
serv_addr.sin_family = AF_INET ;

bcopy ((char * )server->h_addr , (char * )&serv_addr.sin_addr.s_addr , server->h_length);


serv_addr.sin_port = htons(portno);

if (connect(sockfd,&serv_addr,sizeof(serv_addr)) < 0)
{
error("ERROR connecting");
}
printf("Please enter the message: ");
bzero(buffer,256);
fgets(buffer,255,stdin);
n = write(sockfd,buffer,strlen(buffer));
if (n < 0)
{
error("ERROR writing to socket");
}
bzero(buffer,256);
n = read(sockfd,buffer,255);
if (n < 0)
{
error("ERROR reading from socket");
}
printf("%s\n",buffer);

return 0;
}

et voila les warning :

client.c: In function 'error':
client.c:10:1: warning: incompatible implicit declaration of built-in function 'exit' [enabled by default]
 exit(0);
 ^
client.c: In function 'main':
client.c:24:1: warning: incompatible implicit declaration of built-in function 'exit' [enabled by default]
 exit(0);
 ^
client.c:41:11: warning: incompatible implicit declaration of built-in function 'exit' [enabled by default]
           exit(0);
           ^
client.c:46:1: warning: incompatible implicit declaration of built-in function 'bzero' [enabled by default]
 bzero((char *) &serv_addr ,sizeof((serv_addr));
 ^
client.c:46:47: error: expected ')' before ';' token
 bzero((char *) &serv_addr ,sizeof((serv_addr));
                                               ^
client.c:75:1: error: expected ';' before '}' token
 }
 ^