Socket-server and client description

Server description # include <errno. h> // handle some error messages # include <stdio. h> // standard input and output # include <sys/types. h> // Basic System Data Type # include <netinet/in. h> // Internet address family defines the address family like sockaddr_in # include <sys/socket. h> // socket # include <unistd. h> // the header file of the system-defined symbolic constant, which contains the function prototypes of many UNIX system services, such as read and write Functions # include <netdb. h> // netdb. h defines network-related structures, variable types, macros, and functions. For example, struct hostent * gethostbyaddr (const void * addr, size_t len, int type); # include <arpa/inet. h> // defines inet_addr # include <fcntl. h> // fcntl. h defines many macros and open, fcntl function prototype close, etc. # include <stdlib. h> // standard library # include <string. h> // stringint main (int argc, const char * argv []) {int sfp, nfp; // socket descriptor struct sockaddr_in s_add, c_add; // The server and client addresses unsigned int sin_size; unsigned short portnum = 3000; // bind the port number printf ("Hello, Welcome to my server! \ R \ n "); sfp = socket (AF_INET, SOCK_STREAM, 0); // socket descriptor if (-1 = sfp) // if it fails {printf ("socket fail! \ R \ n "); return-1;} printf (" socket OK! \ R \ n "); bzero (& s_add, sizeof (struct sockaddr_in); // clear 0 s_add.sin_family = AF_INET; s_add.sin_addr.s_addr = htonl (INADDR_ANY ); // any address s_add.sin_port = htons (portnum); // port number if (-1 = bind (sfp, (struct sockaddr *) (& s_add ), sizeof (struct sockaddr) // if binding fails {printf ("bind fail! \ R \ n "); return-1;} printf (" bind OK! \ R \ n "); if (-1 = listen (sfp, 5) // if listen fails {printf (" listen fail! \ R \ n "); return-1;} printf (" listen OK \ r \ n "); while (1) {sin_size = sizeof (struct sockaddr_in ); nfp = accept (sfp, (struct sockaddr *) (& c_add), & sin_size); // continuously accept // If accpet succeeds, some client information is in c_add if (-1 = nfp) // failed {printf ("accept fail! \ R \ n "); return-1;} printf (" accept OK! \ R \ nServer start get connect from % # x: % # x \ r \ n ", ntohl (c_add.sin_addr.s_addr), ntohs (c_add.sin_port )); // print the client address and port if (-1 = write (nfp, "hello, welcome to my server \ r \ n", 32 )) // write data {printf ("write fail! \ R \ n "); return-1;} printf (" write OK! \ R \ n "); close (nfp); // close} close (sfp); // close return 0;} client description # include <errno. h> # include <stdio. h> # include <sys/types. h> # include <netinet/in. h> # include <sys/socket. h> # include <unistd. h> # include <netdb. h> # include <arpa/inet. h> # include <fcntl. h> # include <stdlib. h> # include <string. h> int main () {int cfd; // socket descriptor ssize_t recbytes; // accept byte length char buffer [1024] = {0 }; // receive the byte cache area struct sockaddr_in s_add; // The connected address un Signed short portnum = 3000; // connection port printf ("Hello, welcome to client! \ R \ n "); cfd = socket (AF_INET, SOCK_STREAM, 0); if (-1 = cfd) {printf (" socket fail! \ R \ n "); return-1;} printf (" socket OK! \ R \ n "); bzero (& s_add, sizeof (struct sockaddr_in); // clear s_add.sin_family = AF_INET; s_add.sin_addr.s_addr = inet_addr (" 192.168.1.101 "); s_add.sin_port = htons (portnum); printf ("s_addr = % # x, port: % # x \ r \ n", s_add.sin_addr.s_addr, s_add.sin_port ); if (-1 = connect (cfd, (struct sockaddr *) (& s_add), sizeof (struct sockaddr) // start to connect {printf ("connect fail! \ R \ n "); return-1;} printf (" connect OK! \ R \ n "); ssize_t num = 1024; if (-1 = (recbytes = read (cfd, buffer, num ))) // If read fails {printf ("read data fail! \ R \ n "); return-1;} printf (" read OK \ r \ nREC: \ r \ n "); buffer [recbytes] = '\ 0 '; printf ("% s \ r \ n", buffer); getchar (); close (cfd); return 0 ;}