C++通过url直接下载图片并保存

#include 
#include"down.h"
#include 
#include 
#include 
#include 
using namespace std;
#pragma comment(lib,"urlmon.lib")
#pragma comment(lib,"ws2_32.lib")
#void down(string url, string SavePath);

void down(string url, string savepath)
{
  /*  time_t lt;
    lt = time(NULL);
    url = url + "?" + to_string(lt);*/
    size_t len = url.length();//获取字符串长度
    int nmlen = MultiByteToWideChar(CP_ACP, 0, url.c_str(), len + 1, NULL, 0);//如果函数运行成功，并且cchWideChar为零，
                                                                              //返回值是接收到待转换字符串的缓冲区所需求的宽字符数大小。
    wchar_t* buffer = new wchar_t[nmlen];
    MultiByteToWideChar(CP_ACP, 0, url.c_str(), len + 1, buffer, nmlen);




    //DeleteUrlCacheEntry(imgsavepath);
    DeleteUrlCacheEntry(buffer);

    HRESULT hr = URLDownloadToFile(NULL, buffer, _T(".\\temp\\0.jpg"), 0, NULL);
    if (hr == S_OK)
    {
        cout << "-------下载完成---------------------" << endl;
    }
    else
    {
        cout << "---------------图片下载失败---------------------------" << endl;
    }
}

上面的方法存在一个致命问题就是占用磁盘增加，导致最后磁盘爆满，后面采用了另外一种方法

void download(const char* Url, const char* save_as)
{
    
    byte Temp[MAXBLOCKSIZE];
    ULONG Number = 1;

    FILE* stream;
    HINTERNET hSession = InternetOpen("RookIE/1.0", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
    if (hSession != NULL)
    {
        HINTERNET handle2 = InternetOpenUrl(hSession, 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;
    }
}