TCP/IP-based c ++ network programming (API function Edition)

Source code: http://download.csdn.net/detail/nuptboyzhb/4169959

Network Programming Based on TCP/IP protocol

Define variable -- get Winsock version -- load Winsock database -- initialize -- create socket
-- Set socket options -- close socket -- uninstall Winsock database -- release all resources

The entire program architecture is divided into two parts: the Server Client.

Server socket program process:

Socket () → BIND () → listen → accept () → Recv ()/send () → closesocket ()

Client:

Socket → BIND () → connect () → send ()/Recv () → closesocket ()

 

Programming example:

The format of the message to be sent is as follows:

Typedef struct

{

Int ID;

Char data [255];

} Tcpmessage;

The application header file is as follows:

# Include <winsock2.h>

# Pragma comment (Lib, "ws2_32 ")

# Include <stdio. h>

Port: 4500

Server:

1. Initialization:

Wsadata;

Word sockversion = makeword (2, 2 );

If (wsastartup (sockversion, & wsadata )! = 0)

Return 0;

2. Create a socket:

Socket slisten = socket (af_inet, sock_stream, ipproto_tcp );

If (slisten = invalid_socket)

{

Printf ("socket error \ n ");

Return 0;

}

3. Bind the socket to the local address

// Load the address information in the sockaddr_in Structure

Sockaddr_in sin;

Sin. sin_family = af_inet;

Sin. sin_port = htons (4500); // The htons function converts the unsigned short integer number of the host into a network

// Byte order

Sin. sin_addr.s_un.s_addr = inaddr_any;

If (BIND (slisten, (lpsockaddr) & sin, sizeof (SIN) = socket_error)

{

Printf ("BIND error \ n ");

Closesocket (slisten );

Return 0;

}

4. listening port

If (Listen (slisten, 5)= Socket_error)

{

Printf ("Listen error \ n ");

Closesocket (slisten );

Return 0;

}

5. Wait for the connection to be accepted (if there is no connection, keep waiting)

Socket sclient; // used to save the socket returned by accept

Sclient = accept (slisten, 0, 0 );/If the/accept function fails to be called, the connection continues.

If (sclient = invalid_socket)

{

Printf ("accept () error ");

}

6. Use the socket returned by the accept function in step 1 for sending and receiving communication.

6.1 receive: (if not, wait !)

TcpmessageRevdata; // Defines the struct variable for receiving messages

Int ret =Recv(Sclient,(Char *) & revdata, Sizeof (Revdata), 0 );

If (Ret> 0) // indicates that the byte is received.

{

Switch (revdata. ID) // different IDS can have different responses.

{

Case 1:

........

Case 2:

........

}

}

6.2 sending:

TcpmessageSenddata;

Memset ((Char *) & senddata, 0, sizeof (Senddata); // Initialization is 0

Senddata. ID = 1; // assign a value to the ID member variable

Strcpy (senddata. Data, "\ r \ n .. character information to be sent ");

If (Send (sclient, (char *) & senddata, sizeof (senddata), 0)= Socket_error)

{

Char error [10];

Int errorcode = wsagetlasterror ();

ITOA (errorcode, error, 10 );

MessageBox (null, error, "failed to send, error code:", mb_ OK );

Printf ("send error! ");

}

7. Disable

Closesocket (sclient); // socket generated by accept

Closesocket (slisten); // server socket

Wsacleanup ();

Client

1. Initialization

Wsadata;

Word sockversion = makeword (2, 2 );

If (wsastartup (sockversion, & wsadata )! = 0)

Return 0;

2. Create a socket

Socket sclient = socket (af_inet, sock_stream, ipproto_tcp );

If (sclient = invalid_socket)

{

Printf ("socket error \ n ");

Return 0;

}

3. Bind the socket to the local address

// Load the server address information in the sockaddr_in Structure

Sockaddr_in servaddr;

Servaddr. sin_family = af_inet;

Servaddr. sin_port = htons (4500); // The htons function converts the unsigned short integer number of the host to the network

// In byte order, port 4500 is the port to connect to the server

Servaddr. sin_addr.s_un.s_addr = inet_addr ("127.0.0.1"); // server IP Address

4. Connect to the server

If (connect (sclient, (sockaddr *) & servaddr, sizeof (servaddr) = socket_error)

{

Printf ("Connect error \ n ");

Closesocket (sclient );

Return 0;

}

// Note: Open the server first; otherwise, the connection fails.

5. send and receive communications

Use the send and Recv functions, which are the same as those on the server.

6. Disable

Closesocket (sclient); // The client has only one connection socket

Wsacleanup ();