用C语言与Winsock完成一对一Socket客户端和用户端程序

以下是一个简单的基于Winsock的一对一Socket客户端和服务器端程序的示例，使用C语言编写：

客户端程序：

#include <stdio.h>
#include <winsock2.h>

#pragma comment(lib, "ws2_32.lib")

int main()
{
    WSADATA wsaData;
    int iResult;

    iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != 0)
    {
        printf("WSAStartup failed: %d\n", iResult);
        return 1;
    }

    SOCKET ConnectSocket;
    ConnectSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (ConnectSocket == INVALID_SOCKET)
    {
        printf("socket failed: %ld\n", WSAGetLastError());
        WSACleanup();
        return 1;
    }

    struct sockaddr_in clientService;
    clientService.sin_family = AF_INET;
    clientService.sin_addr.s_addr = inet_addr("127.0.0.1");
    clientService.sin_port = htons(27015);

    iResult = connect(ConnectSocket, (SOCKADDR*)&clientService, sizeof(clientService));
    if (iResult == SOCKET_ERROR)
    {
        printf("connect failed: %d\n", WSAGetLastError());
        closesocket(ConnectSocket);
        WSACleanup();
        return 1;
    }

    char sendbuf[1024] = {0};
    char recvbuf[1024] = {0};

    while (1)
    {
        printf("Enter message to send:");
        fgets(sendbuf, 1024, stdin);

        iResult = send(ConnectSocket, sendbuf, strlen(sendbuf), 0);
        if (iResult == SOCKET_ERROR)
        {
            printf("send failed: %d\n", WSAGetLastError());
            closesocket(ConnectSocket);
            WSACleanup();
            return 1;
        }

        iResult = recv(ConnectSocket, recvbuf, 1024, 0);
        if (iResult > 0)
        {
            printf("Message received: %s\n", recvbuf);
        }
        else if (iResult == 0)
        {
            printf("Connection closed\n");
            break;
        }
        else
        {
            printf("recv failed: %d\n", WSAGetLastError());
            closesocket(ConnectSocket);
            WSACleanup();
            return 1;
        }
    }

    closesocket(ConnectSocket);
    WSACleanup();
    return 0;
}

服务器端程序：

#include <stdio.h>
#include <winsock2.h>

#pragma comment(lib, "ws2_32.lib")

int main()
{
    WSADATA wsaData;
    int iResult;

    iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != 0)
    {
        printf("WSAStartup failed: %d\n", iResult);
        return 1;
    }

    SOCKET ListenSocket;
    ListenSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (ListenSocket == INVALID_SOCKET)
    {
        printf("socket failed: %ld\n", WSAGetLastError());
        WSACleanup();
        return 1;
    }

    struct sockaddr_in service;
    service.sin_family = AF_INET;
    service.sin_addr.s_addr = INADDR_ANY;
    service.sin_port = htons(27015);

    iResult = bind(ListenSocket, (SOCKADDR*)&service, sizeof(service));
    if (iResult == SOCKET_ERROR)
    {
        printf("bind failed: %d\n", WSAGetLastError());
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }

    iResult = listen(ListenSocket, SOMAXCONN);
    if (iResult == SOCKET_ERROR)
    {
        printf("listen failed: %d\n", WSAGetLastError());
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }

    SOCKET ClientSocket;
    ClientSocket = accept(ListenSocket, NULL, NULL);
    if (ClientSocket == INVALID_SOCKET)
    {
        printf("accept failed: %d\n", WSAGetLastError());
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }

    char recvbuf[1024] = {0};
    char sendbuf[1024] = {0};

    while (1)
    {
        iResult = recv(ClientSocket, recvbuf, 1024, 0);
        if (iResult > 0)
        {
            printf("Message received: %s\n", recvbuf);

            sprintf(sendbuf, "Received message: %s", recvbuf);
            iResult = send(ClientSocket, sendbuf, strlen(sendbuf), 0);
            if (iResult == SOCKET_ERROR)
            {
                printf("send failed: %d\n", WSAGetLastError());
                closesocket(ClientSocket);
                WSACleanup();
                return 1;
            }
        }
        else if (iResult == 0)
        {
            printf("Connection closed\n");
            break;
        }
        else
        {
            printf("recv failed: %d\n", WSAGetLastError());
            closesocket(ClientSocket);
            WSACleanup();
            return 1;
        }
    }

    closesocket(ClientSocket);
    closesocket(ListenSocket);
    WSACleanup();
    return 0;
}

注意：以上示例仅为演示目的，未进行错误处理等完整的实现。在实际开发中，需要进行更完整的错误处理。