UDP-based Winsock programming (C ++)

UDP-based Winsock programming (C ++)

Compared with TCP-based Winsock programming, UDP-based Winsock programming lacks only one step. The Server is missingAccept connection(Accept () function call); for the Client,Request connection(Connect () function call ).

In addition, the difference is that in UDP, the data sending and receiving functions are sendto () and recvfrom.
Function prototype:

Int sendto (SOCKET s, const char FAR * buf, int len, int flags, const struct sockaddr FAR * to, int tolen );
Int recvfrom (SOCKET s, char FAR * buf, int len, int flags, struct sockaddr FAR * to, int FAR * fromlen );

Parameter flagsGenerally, it is set to 0;
ParameterIt is the target address structure information;
Parameter tolenThe size of the target address structure;

Let alone code!

Code:

Server

/* UDPServer. cpp */# include
  
   
# Include
   
    
# Include
    
     
# Pragma comment (lib, "WS2_32.lib") int main () {// initialize the socket library WSADATA data; // define the struct variable WORD w = MAKEWORD (2, 0 ); // define the socket version: WSAStartup (w, & data); // initialize the socket library char sztext [] = "Welcome \ r \ n "; // create SOCKET handle socket s; s =: SOCKET (AF_INET, SOCK_DGRAM, 0); // create UDP socket // address structure settings and byte conversion sockaddr_in addr and addr2; // create the socket address Structure Variable int n = sizeof (addr2); // The address structure variable size char buff [11] = {0}; // receives the data buffer addr. sin_family = AF_INET; addr. sin_port = htons (75); addr. sin_ad Dr. s_un.S_addr = INADDR_ANY; // bind socket: bind (s, (sockaddr *) & addr, sizeof (addr )); printf ("UDP server started \ r \ n"); // The while (true) Prompt {// receive data from the client if (: recvfrom (s, buff, 10, 0, (sockaddr *) & addr2, & n )! = 0) {printf ("% s connected \ r \ n", inet_ntoa (addr2.sin _ addr); printf ("% s \ r \ n", buff ); // send data to the client: sendto (s, sztext, sizeof (sztext), 0, (sockaddr *) & addr2, n); break ;}// close the socket:: closesocket (s); // close the socket Library: WSACleanup (); if (getchar () {return 0;} else {: Sleep (100 );}}
    
   
  

Client

/* UDPClient. cpp */# include
  
   
# Include
   
    
# Include
    
     
# Pragma comment (lib, "WS2_32.lib") // connect the socket library int main () {// initialize the socket library WSADATA data; // parameter 1 WORD w = MAKEWORD (2, 0 ); // parameter 2, indicating that the socket version is 2.0: WSAStartup (w, & data); char sztext [] = "Hello, server! \ R \ n "; // create SOCKET handle socket s; s =: SOCKET (AF_INET, SOCK_DGRAM, 0 ); // create a UDP socket // address structure setting and byte conversion sockaddr_in addr, addr2; int n = sizeof (addr2); char buff [10] = {0}; addr. sin_family = AF_INET; addr. sin_port = htons (75); addr. sin_addr.S_un.S_addr = inet_addr ("127.0.0.1"); printf ("UDP client started \ r \ n"); // send information to the server if (: sendto (s, sztext, sizeof (sztext), 0, (sockaddr *) & addr, n )! = 0) {// receiving information from the slave server: recvfrom (s, buff, 10, 0, (sockaddr *) & addr2, & n); printf ("the server says: % s \ r \ n ", buff); // close socket: closesocket (s); // close socket Library: WSACleanup ();} if (getchar ()) {return 0;} else {: Sleep (100 );}}