windows使用winsock库实现一个TCP/UDP的客户机服务器模式的聊天程序案例

以下是使用winsock库实现TCP/UDP客户端服务器聊天程序的示例代码：

服务器端代码：

#include <iostream>
#include <winsock2.h>

#pragma comment(lib,"ws2_32.lib") //Winsock Library

int main(int argc, char* argv[])
{
    WSADATA wsa;
    SOCKET s, new_socket;
    struct sockaddr_in server, client;
    int c;
    char* message;

    std::cout << "\nInitialising Winsock...";

    if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
    {
        std::cout << "Failed. Error Code : " << WSAGetLastError();
        return 1;
    }

    std::cout << "Initialised.\n";

    //Create a socket
    if ((s = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
    {
        std::cout << "Could not create socket : " << WSAGetLastError();
    }

    std::cout << "Socket created.\n";

    //Prepare the sockaddr_in structure
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY;
    server.sin_port = htons(8888);

    //Bind
    if (bind(s, (struct sockaddr*)&server, sizeof(server)) == SOCKET_ERROR)
    {
        std::cout << "Bind failed with error code : " << WSAGetLastError();
        exit(EXIT_FAILURE);
    }

    std::cout << "Bind done.\n";

    //Listen to incoming connections
    listen(s, 3);

    //Accept and incoming connection
    std::cout << "Waiting for incoming connections...\n";

    c = sizeof(struct sockaddr_in);
    while ((new_socket = accept(s, (struct sockaddr*)&client, &c)) != INVALID_SOCKET)
    {
        std::cout << "Connection accepted.\n";

        //Reply to the client
        message = "Hello Client, I have received your connection. And now I will assign a name for you.\n";
        send(new_socket, message, strlen(message), 0);

        //Receive a reply from the client
        int recv_size;
        char client_reply[2000];
        while ((recv_size = recv(new_socket, client_reply, 2000, 0)) != SOCKET_ERROR)
        {
            //Add a NULL terminating character to make it a proper string before printing
            client_reply[recv_size] = '\0';
            std::cout << "Client: " << client_reply << std::endl;

            //Reply to the client
            message = "Hello Client, I have received your message.\n";
            send(new_socket, message, strlen(message), 0);
        }

        if (recv_size == SOCKET_ERROR)
        {
            std::cout << "recv failed with error code : " << WSAGetLastError();
        }
    }

    if (new_socket == INVALID_SOCKET)
    {
        std::cout << "accept failed with error code : " << WSAGetLastError();
        return 1;
    }

    closesocket(s);
    WSACleanup();

    return 0;
}

客户端代码：

#include <iostream>
#include <winsock2.h>

#pragma comment(lib,"ws2_32.lib") //Winsock Library

int main(int argc, char* argv[])
{
    WSADATA wsa;
    SOCKET s;
    struct sockaddr_in server;
    char* message, server_reply[2000];

    std::cout << "\nInitialising Winsock...";

    if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
    {
        std::cout << "Failed. Error Code : " << WSAGetLastError();
        return 1;
    }

    std::cout << "Initialised.\n";

    //Create a socket
    if ((s = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
    {
        std::cout << "Could not create socket : " << WSAGetLastError();
    }

    std::cout << "Socket created.\n";

    server.sin_addr.s_addr = inet_addr("127.0.0.1");
    server.sin_family = AF_INET;
    server.sin_port = htons(8888);

    //Connect to remote server
    if (connect(s, (struct sockaddr*)&server, sizeof(server)) < 0)
    {
        std::cout << "connect error\n";
        return 1;
    }

    std::cout << "Connected.\n";

    //Receive a reply from the server
    int recv_size;
    while ((recv_size = recv(s, server_reply, 2000, 0)) != SOCKET_ERROR)
    {
        //Add a NULL terminating character to make it a proper string before printing
        server_reply[recv_size] = '\0';
        std::cout << "Server: " << server_reply << std::endl;

        //Send some data
        message = "Hello Server, I am a client.\n";
        send(s, message, strlen(message), 0);
    }

    if (recv_size == SOCKET_ERROR)
    {
        std::cout << "recv failed with error code : " << WSAGetLastError();
    }

    closesocket(s);
    WSACleanup();

    return 0;
}

这个程序实现了一个简单的TCP聊天程序，当客户端连接到服务器时，服务器会向客户端发送一条欢迎信息，然后等待接收客户端发送的消息并回复给客户端。客户端连接到服务器后，会收到欢迎信息，然后不断发送消息给服务器并等待回复。