code: добавил вывод ошибки и загрузку с сервера

main.cpp

@@ -5,6 +5,8 @@
 #include "text.h"
 #include "svg.h"
 #include <curl/curl.h>
+#include <sstream>
+#include <string>
 
 using namespace std;
 
@@ -28,38 +30,57 @@ input_data(istream& in, bool prompt)
     ik.numbers.resize(number_count);
     for (size_t i =0; i < number_count; i++)
     {
-        cin >> ik.numbers[i];
+        in >> ik.numbers[i];
     }
     if (prompt)
     cerr<< "Enter bin count: ";
-    cin >> ik.bin_count;
+    in >> ik.bin_count;
     return ik;
 }
 
-int main(int argc, char* argv[])
+size_t write_data(void* items, size_t item_size, size_t item_count, void* ctx)
 {
-    if (argc > 1){
+    size_t data_size = item_size * item_count;
+    stringstream* buffer = reinterpret_cast<stringstream*>(ctx);
+    buffer->write(reinterpret_cast<const char*>(items), data_size);
+    return data_size;
+}
 
+Input
+download(const string& address)
+{
+    stringstream buffer;
     CURL *curl = curl_easy_init();
-
     if(curl)
     {
         CURLcode res;
-            curl_easy_setopt(curl, CURLOPT_URL, argv[1]);
+        curl_easy_setopt(curl, CURLOPT_URL, address.c_str());
+        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
+        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &buffer);
         res = curl_easy_perform(curl);
-            curl_easy_cleanup(curl);
         if (res != CURLE_OK)
         {
-                cout << curl_easy_strerror;
+            fprintf(stderr, "curl_easy_perform() failed: %s\n",curl_easy_strerror(res));
             exit(1);
         }
+        curl_easy_cleanup(curl);
     }
-        return 0;
+
+    return input_data(buffer, false);
+}
+
+int main(int argc, char* argv[])
+{
+    Input input;
+    if (argc > 1)
+    {
+        input = download(argv[1]);
+    }
+    else
+    {
+        input = input_data(cin, true);
     }
-    curl_global_init(CURL_GLOBAL_ALL);
+    const auto bins = make_histogram(input.numbers, input.bin_count);
-    auto in = input_data(cin, true);
-    auto bins = make_histogram(in.numbers, in.bin_count);
     show_histogram_svg(bins);
-    getch();
     return 0;
 }