代码示例：在Windows中用C++完成TCP服务端接收到特定字符串，主函数执行相应命令

可以使用以下代码示例在Windows中用C完成TCP服务端接收到特定字符串，主函数执行相应命令：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winsock2.h>
 
#pragma comment(lib, "ws2_32.lib")
 
int main() {
    WSADATA wsaData;
    SOCKET serverSock;
    SOCKET clientSock;
    struct sockaddr_in sin;
    int port = 8888; // 服务端口号
    char recvBuf[1024] = {0}; // 接收缓冲区
    char respBuf[1024] = {0}; // 响应缓冲区
 
    // 初始化Winsock
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        printf("Failed to initialize Winsock.\n");
        return 1;
    }
 
    // 创建TCP套接字
    serverSock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (serverSock == INVALID_SOCKET) {
        printf("Failed to create socket.\n");
        WSACleanup();
        return 1;
    }
 
    // 绑定端口
    memset(&sin, 0, sizeof(sin));
    sin.sin_family = AF_INET;
    sin.sin_port = htons(port);
    sin.sin_addr.s_addr = htonl(INADDR_ANY);
    if (bind(serverSock, (struct sockaddr *)&sin, sizeof(sin)) == SOCKET_ERROR) {
        printf("Failed to bind socket.\n");
        closesocket(serverSock);
        WSACleanup();
        return 1;
    }
 
    // 开始监听
    if (listen(serverSock, SOMAXCONN) == SOCKET_ERROR) {
        printf("Failed to listen on socket.\n");
        closesocket(serverSock);
        WSACleanup();
        return 1;
    }
 
    printf("TCP server is running on port %d...\n", port);
 
    // 等待连接
    while (1) {
        clientSock = accept(serverSock, NULL, NULL);
        if (clientSock == INVALID_SOCKET) {
            printf("Failed to accept client.\n");
            continue;
        }
 
        // 接收数据
        memset(recvBuf, 0, sizeof(recvBuf));
        if (recv(clientSock, recvBuf, sizeof(recvBuf) - 1, 0) == SOCKET_ERROR) {
            printf("Failed to receive data from client.\n");
            closesocket(clientSock);
            continue;
        }
 
        // 判断收到的字符串是否为特定字符串
        if (strcmp(recvBuf, "special string") == 0) {
            // 执行相应命令
            printf("Received command: do something.\n");
            strcpy(respBuf, "Command executed.");
        } else {
            strcpy(respBuf, "Invalid command.");
        }
 
        // 发送响应数据
        if (send(clientSock, respBuf, strlen(respBuf), 0) == SOCKET_ERROR) {
            printf("Failed to send response to client.\n");
            closesocket(clientSock);
            continue;
        }
 
        printf("Response sent to client: %s\n", respBuf);
 
        // 关闭连接
        closesocket(clientSock);
    }
 
    // 关闭套接字
    closesocket(serverSock);
 
    // 终止Winsock
    WSACleanup();
 
    return 0;
}

上述代码创建了一个TCP服务端，监听端口为8888。当服务端接收到客户端发送的字符串为“special string”时，服务端会执行相应命令，并将响应发送给客户端。其他字符串会被视为无效命令。