[英]error: cannot convert ‘std::string {aka std::basic_string<char>}’ to ‘char*’ in initialization
[英]error: cannot convert ‘std::string’ to ‘char*’ in initialization
我有從網頁下載匯率的python腳本,我想從中制作c ++程序,這是我到目前為止的內容:
include iostream
include time.h
include stdio.h
include curl/curl.h
include curl/easy.h
include string
define CURL_STATICLIB
using namespace std;
void dat(string &d){
time_t rawtime;
struct tm * timeinfo;
char datum[80];
time ( &rawtime );
timeinfo=localtime(&rawtime);
strftime(datum,80,"%d%m%y",timeinfo);
d=datum;
}
size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream) {
size_t written;
written = fwrite(ptr, size, nmemb, stream);
return written;
}
int main()
{
string f;
dat(f);
string l1="http://www.hnb.hr/tecajn/f";
string l2=".dat";
string linkz=l1+f+l2;
cout << linkz;
CURL *curl;
FILE *fp;
CURLcode res;
char *url = linkz;
char outfilename[FILENAME_MAX] = "/home/tomi/data.txt";
curl = curl_easy_init();
if (curl) {
fp = fopen(outfilename,"wb");
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
fclose(fp);
return 0;
}
當我嘗試編譯時,它給了我這個錯誤,我發現使用algorythm來下載txt,所以我希望它是正確的
如果您已經指出發生錯誤的那一行,那么我就不必追溯到:
string linkz=l1+f+l2;
...
char *url = linkz;
您可以使用c_str()
獲取指向字符串中const字符的指針。 這樣就可以了:
char const* url = linkz.c_str();
您可以在setopt
調用中使用同一行,或者將url
設置為std::string
。
char *url = linkz;
應該是const char* url = linkz.c_str();
假設出於API原因您確實需要C樣式的字符串。
問題在這一行:
char *url = linkz;
“鏈接”是std :: string,但是“ url”是char *。 嘗試使用string的c_str方法來獲得所需的內容,如下所示:
const char * url = links.c_str();
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