学步园

C++Builder6的代码如下：

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
#include "urlmon.h"
#include "stdio.h"
#pragma link "D:\\Program Files\\Borland\\CBuilder6\\Lib\\Psdk\\urlmon.lib"//此处根据你的实际情况修改
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------

void __fastcall TForm1::Button1Click(TObject *Sender)
{
    int APIENTRY WinMain(HINSTANCE hInstance,
                         HINSTANCE hPrevInstance,
                         LPSTR     lpCmdLine,
                         int       nCmdShow);
    {
        char buf[MAX_PATH] = {0};
        char chTempIp[128];
        char chIP[64];
        URLDownloadToFile(0,"http://www.ip138.com/ip2city.asp","IPinTheWorld.ini",0,NULL);
        FILE *fp=fopen( "IPinTheWorld.ini", "r" );

        if ( fp != NULL )
        {
            fseek(fp, 0, SEEK_SET);
            fread(buf,1,256,fp);
            fclose(fp);
            char* iIndex = strstr(buf,"[");
            if (iIndex)
            {
                sprintf( chTempIp,"%s",iIndex);
                int nBuflen = strlen(chTempIp);
                for (int i =0; i<nBuflen; i++)
                {
                    chIP[i] = chTempIp[i+1];
                    if (chTempIp[i] == ']')
                    {
                        chIP[i-1] = '\0';
                        DeleteFile("IPinTheWorld.ini");
                        continue;
                    }

                }
            }

        }
        MessageBox(NULL, chIP,chIP,0);
    }
}
//---------------------------------------------------------------------------

 参考：http://blog.csdn.net/hacksouls/article/details/3511762