How to Merge Multiple Excel (XLSX) Files Together using C/C++

Looking for an easy & convenient way to combine data from multiple Excel spreadsheets into a single, comprehensive document? The below code might solve your problem. You can use these C/C++ examples to programmatically conjoin up to 10 XLSX files in a single API request, and you can do so for free (with a limit of 800 API calls per month) by authenticating your requests with a free-tier API key.

You’ll first need to install Libcurl in your C/C++ project:

libcurl/7.75.0

With that out of the way, you can copy & paste the below code into your file, and you’re all set:

CURL *curl;
CURLcode res;
curl = curl_easy_init();
if(curl) {
     curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "POST");
     curl_easy_setopt(curl, CURLOPT_URL, "https://api.cloudmersive.com/convert/merge/xlsx/multi");
     curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
     curl_easy_setopt(curl, CURLOPT_DEFAULT_PROTOCOL, "https");
     struct curl_slist *headers = NULL;
     headers = curl_slist_append(headers, "Content-Type: multipart/form-data");
     headers = curl_slist_append(headers, "Apikey: YOUR-API-KEY-HERE");
     curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
     curl_mime *mime;
     curl_mimepart *part;
     mime = curl_mime_init(curl);
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile1");
     curl_mime_filedata(part, "/path/to/file");
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile2");
     curl_mime_filedata(part, "/path/to/file");
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile3");
     curl_mime_filedata(part, "/path/to/file");
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile4");
     curl_mime_filedata(part, "/path/to/file");
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile5");
     curl_mime_filedata(part, "/path/to/file");
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile6");
     curl_mime_filedata(part, "/path/to/file");
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile7");
     curl_mime_filedata(part, "/path/to/file");
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile8");
     curl_mime_filedata(part, "/path/to/file");
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile9");
     curl_mime_filedata(part, "/path/to/file");
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile10");
     curl_mime_filedata(part, "/path/to/file");
     curl_easy_setopt(curl, CURLOPT_MIMEPOST, mime);
     res = curl_easy_perform(curl);
     curl_mime_free(mime);
}
curl_easy_cleanup(curl);