socket programming steps

How to implement socket network programming in C under windows, what header files or libraries are needed?

The header files to be used include:

#include<winsock2.h>

#include<windows.h>

Compared with the socket programming in Linux environment, the windows environment has an extra step: startup or initialize the winsock library

Winsock, a standard API, is a network programming interface for data communication between two or more applications (or processes) over a network. There are two versions:

Winsock1:

WindowsCE platform support.

Header file: WinSock.h

Library: wsock32.lib

Winsock2:

Some platforms, such as WindowsCE, do not appear to be supported. It can be distinguished from the Winsock1 version by the prefix WSA. Individual functions such as WSAStartup, WSACleanup, WSARecvEx, WSAGetLastError all belong to the Winsock1.1 specification;

Header file: WinSock2.h

Library: ws2_32.lib

mswsock.h is used as a Programming extensions, use must link mswsock.dll

Extensions

winsock library load and unload:

Load: intWSAStartup(WORDwVersionRequested,LPWSADATAlpWSAData);< /p>

Load successfully, the return value is 0.

WORDwVersionRequested: the version of winsock loaded, using the macro MAKEWORD(x,y), x means high byte, y means low byte. However when used MAKEWORD(2,2). The high byte is the same as the low byte~~

LPWSADATAlpWSAData: a pointer to the WSADATA structure, which is passed in as a parameter, and the system helps us populate the version information. If you are interested, you can take a look at the contents of the structure, but it’s basically useless.

Unload: intWSACleanup(void); The unload function is really easy and pleasant compared to load.

How to implement java one to one chat room? Can you introduce it

To implement a one-to-one chat room in Java, you can use socket programming to implement communication based on the TCP protocol.

Here are some general steps:

Creating a server-side program: a server-side program is created that waits for a connection request from the client. On the arrival of a connection request, the server creates a new thread to handle the connection request.

Creating a client program: creates a client program that connects to the server-side program. After a successful connection, the client can send messages to the server, which the server forwards to the receiver.

Implementing message transfer: between the client and the server, data is transferred through input streams and output streams. When the client sends a message to the server, it uses the output stream to send the message to the server; when the server receives the message, it uses the input stream to read the message content.

Enabling One-to-One Communication: When the client and the server establish a connection, one-to-one communication can be realized by specifying the recipient’s username. When a client sends a message to the server, it needs to specify the recipient’s username, and the server will find the corresponding client based on the username and send the message to the specified client.

Implementation of interface interaction: JavaFX, Swing and other graphical interface libraries can be used to realize the display of the chat window and user input. After the user enters a message in the chat window, the client sends the message to the server, and the server forwards the message to the receiver.

It should be noted that, in order to ensure the reliability and security of communication, the data needs to be encrypted and verified, but also need to consider the issue of concurrent access to prevent multiple threads accessing at the same time resulting in data misalignment.

The general steps for programming network communication using sockets in C# are

1.Create socket

2.Determine the local computer endpoint (ip and port number)

3.socket binds the endpoint

4.socket.receive();Receive data

5. socket.send();send data

6. socket.close();close socket

Difference between TCP and UDP in socket programming

UDP and TCP programming steps are also a little different, as follows:

TCP programming on the server side of the general steps are:

1, create a socket, with the function socket();

2, set the socket properties, with the function setsockopt();*Optional

3, bind the IP address, port and other information to the socket, with the function bind();

4, open listening, with the function listen();

5, receive the client up to the connection, with the function accept();

6, send and receive data, with the function send() and recv(), or read() and write();

7, close the network connection;

8, close the listening;

TCP programming client general steps are:

1, create a socket, with the function socket();

2, set the socket attributes, with the function setsockopt();* optional

3, bind the IP address, port and other information to the socket, with the function bind();* optional

4, set the other party to connect to the IP address and port and other attributes;

5, connect to the server, with the function connect ();

6, send and receive data, with the function send () and recv (), or read () and write ();

7, close the network connection;

The corresponding UDP programming steps are much simpler, respectively, are as follows:

The general steps on the server side of UDP programming are:

1, create a socket, with the function socket ();

2, set the socket attributes, with the function setsockopt ();* optional

3, bind the IP address, port and other information to the socket, with the function bind ();

4, cycle to receive data, with the function recvfrom ();

5, close the network connection;

UDP programming of the client’s general steps are:

1, create a socket, with the function socket();

2, set the socket attributes, with the function setsockopt();* optional

3, bind the IP address, port and other information to the socket, with the function bind();* optional

4, set the other party’s IP address and port and other properties;

5, send data, with the function sendto();

6, close the network connection;