下載文件要用到操作系統的API函數，下面是一個WINDOWS系統中的實現：
//---------------------------------------------------------------------------
#include "stdafx.h"
#include <stdio.h>
#include <windows.h>
#include <wininet.h>
#define MAXBLOCKSIZE 1024
#pragma comment( lib, "wininet.lib" ) ;
void download(const char *Url,const char *save_as)/*將Url指向的地址的文件下載到save_as指向的本地文件*/
{
byte Temp[MAXBLOCKSIZE];
ULONG Number = 1;
FILE *stream;
HINTERNET hSession = InternetOpen(_T("RookIE/1.0"), INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
if (hSession != NULL)
{
HINTERNET handle2 = InternetOpenUrl(hSession,_T(Url), NULL, 0, INTERNET_FLAG_DONT_CACHE, 0);
if (handle2 != NULL)
{
if( (stream = fopen( save_as, "wb" )) != NULL )
{
while (Number > 0)
{
InternetReadFile(handle2, Temp, MAXBLOCKSIZE - 1, &Number);
fwrite(Temp, sizeof (char), Number , stream);
}
fclose( stream );
}
InternetCloseHandle(handle2);
handle2 = NULL;
}
InternetCloseHandle(hSession);
hSession = NULL;
}
}
int main(int argc, char* argv[]){
download("*調用示例，下載百度的首頁到c:\index.html文件*/
return 0;
}