使用windows C语言写个局域网测速工具

好的，我可以为您提供一个基于C语言的局域网测速工具的代码示例：

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

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

#define BUFFER_SIZE 1024
#define DEFAULT_PORT 8888

int main(int argc, char* argv[])
{
    WSADATA wsaData;
    SOCKET sockServer, sockClient;
    SOCKADDR_IN addrServer, addrClient;
    char buffer[BUFFER_SIZE];
    int nRet, nAddrLen, nPort;

    // 初始化Winsock
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        printf("WSAStartup failed with error code %d\n", WSAGetLastError());
        return 1;
    }

    // 创建服务器Socket
    sockServer = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sockServer == INVALID_SOCKET) {
        printf("socket failed with error code %d\n", WSAGetLastError());
        WSACleanup();
        return 1;
    }

    // 设置服务器地址
    nPort = DEFAULT_PORT;
    if (argc > 1) {
        nPort = atoi(argv[1]);
    }
    addrServer.sin_family = AF_INET;
    addrServer.sin_port = htons(nPort);
    addrServer.sin_addr.s_addr = htonl(INADDR_ANY);

    // 绑定服务器Socket到地址
    if (bind(sockServer, (SOCKADDR*)&addrServer, sizeof(addrServer)) == SOCKET_ERROR) {
        printf("bind failed with error code %d\n", WSAGetLastError());
        closesocket(sockServer);
        WSACleanup();
        return 1;
    }

    // 开始监听连接请求
    if (listen(sockServer, SOMAXCONN) == SOCKET_ERROR) {
        printf("listen failed with error code %d\n", WSAGetLastError());
        closesocket(sockServer);
        WSACleanup();
        return 1;
    }

    printf("Server is listening on port %d...\n", nPort);

    while (1) {
        // 接受客户端连接请求
        nAddrLen = sizeof(addrClient);
        sockClient = accept(sockServer, (SOCKADDR*)&addrClient, &nAddrLen);
        if (sockClient == INVALID_SOCKET) {
            printf("accept failed with error code %d\n", WSAGetLastError());
            closesocket(sockServer);
            WSACleanup();
            return 1;
        }

        printf("Client connected from %s:%d\n", inet_ntoa(addrClient.sin_addr), ntohs(addrClient.sin_port));

        // 接收客户端数据
        nRet = recv(sockClient, buffer, BUFFER_SIZE, 0);
        if (nRet == SOCKET_ERROR) {
            printf("recv failed with error code %d\n", WSAGetLastError());
            closesocket(sockClient);
            continue;
        }

        // 发送响应数据
        nRet = send(sockClient, buffer, nRet, 0);
        if (nRet == SOCKET_ERROR) {
            printf("send failed with error code %d\n", WSAGetLastError());
            closesocket(sockClient);
            continue;
        }

        printf("Data received and sent back to client.\n");

        // 关闭客户端Socket
        closesocket(sockClient);
    }

    // 关闭服务器Socket
    closesocket(sockServer);

    // 清理Winsock
    WSACleanup();

    return 0;
}

这个程序可以创建一个TCP服务器，监听指定端口的连接请求，并对每个连接请求进行响应。当客户端连接上服务器后，可以向服务器发送任意数据，服务器会将接收到的数据原样返回给客户端。您可以根据自己的需求修改代码，实现局域网测速的功能。

请注意，这个程序只是一个示例，可能存在一些问题和不足之处，您需要根据实际情况进行修改和完善。