C/C++使用socket实现判断ip是否能连通

#include <iostream>  
#include <cstdlib>  
#include <cstdio>  
#include <winsock2.h>
#include <string>
#include <chrono>
 
#pragma comment(lib, "ws2_32.lib")
 
using namespace std;
 
bool canConnectToRouter(string ipAddress) 
{
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)  // 初始化Windows Socket库  
        return false;
 
    int sockfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); // 创建一个TCP socket  
    if (sockfd < 0) 
        return false;
    struct sockaddr_in serveraddr;
    serveraddr.sin_addr.s_addr = inet_addr(ipAddress.c_str());
    serveraddr.sin_family = AF_INET;
    serveraddr.sin_port = htons(139);
 
    int ret = connect(sockfd, (struct sockaddr*)&serveraddr, sizeof(serveraddr)); // 连接服务器  
    if (ret < 0) 
    {
        closesocket(sockfd);
        return false;
    }
 
    closesocket(sockfd);
    return true;
}
 
int main()
{
    for (int i = 0; i < 256; i++)
    {
        string ip = "192.168.16." + to_string(i);
        std::cout << ip << "\t";
        auto start = chrono::steady_clock::now(); // 记录开始时间  
        if (canConnectToRouter(ip.c_str()))
            std::cout << "InCompany\t";
        else
            std::cout << "NotInCompany\t";
        auto end = chrono::steady_clock::now(); // 记录结束时间  
        auto duration = chrono::duration_cast<chrono::milliseconds>(end - start); // 计算执行时间，单位为毫秒  
        cout << "耗时：" << duration.count() << "毫秒" << endl;
    }
    cin.get();
}