c++ socket test

#include <winsock2.h>
#include<iostream>
#include<string>
using namespace std;
#pragma comment(lib,"ws2_32.lib")

string getCommand(SOCKET  s)
{
    string str;
    char  buffer[20];
    while (1)
    {
        int len= recv(s,buffer,20,0);
        if (len>0)
        {
            str+=buffer;
           if (buffer[len-1]=='\n' || buffer[len-1]=='\r')
            {
                break;
            }
        }

    }
    return str;
}
void parseCommand(SOCKET s,string cmd)
{
    if (cmd.substr(0,4)=="user")
    {
        send(s,"ok",4,0);
    }
}
int main()
{
    WSADATA  ws;
    SOCKET s;
    bool isLogin=false;
    // 接受连接
    SOCKET conSocket;
    int ret= WSAStartup(MAKEWORD(2,2),&ws);
    if (ret!=NO_ERROR)
    {
        cout<<"error to load scoket"<<endl;
        return -1;
    }
    s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    sockaddr_in service;
    service.sin_port=htons(1234);
    service.sin_addr.s_addr=inet_addr("127.0.0.1");
    service.sin_family=AF_INET;
    bind(s,(SOCKADDR*)&service,sizeof(service));
    listen(s,10);
    cout<<"--------------------\n";
    cout<<"welcome to ftp server\n";
    cout<<"--------------------\n";

    while (1)
    {
        conSocket=accept(s,NULL,NULL);
        char *buffer="欢迎光临FTP站点！\0";
        string  str;
        if (conSocket)
        {
            send(conSocket,buffer,strlen(buffer)*sizeof(char),MSG_DONTROUTE);
        }
        str=getCommand(conSocket);
        cout<<str;
        parseCommand(conSocket,str);
    }
    closesocket(s);
    WSACleanup();
}