UDP client

#include
#include
#include
#include
#include
#include
void error(char *);
int main(int argc, char *argv[])
{
int sock, length, n;
struct sockaddr_in server, from;
struct hostent *hp;
char buffer[256];
if (argc != 3) { printf("Usage: server port\n");
exit(1);
}
sock= socket(AF_INET, SOCK_DGRAM, 0);
if (sock < 0) error("socket");
server.sin_family = AF_INET;
hp = gethostbyname(argv[1]);
if (hp==0) error("Unknown host");
bcopy((char *)hp->h_addr,(char *)&server.sin_addr,hp->h_length);
server.sin_port = htons(atoi(argv[2]));
length=sizeof(struct sockaddr_in);
printf("Please enter the message: ");
bzero(buffer,256);
fgets(buffer,255,stdin);
n=sendto(sock,buffer,strlen(buffer),0,&server,length);
if (n < 0) error("Sendto");
n = recvfrom(sock,buffer,256,0,&from, &length);
if (n < 0) error("recvfrom");
write(1,"Got an ack: ",12);
write(1,buffer,n);
}
void error(char *msg)
{
perror(msg);
exit(0);
}