общий вариант

main.cpp

@@ -4,6 +4,8 @@
 #include "text.h"
 #include "svg.h"
 #include <curl/curl.h>
+#include <sstream>
+#include <string>
 
 using namespace std;
 
@@ -35,10 +37,44 @@ input_data(istream& in, bool prompt) {
     return inp;
 }
 
+size_t
+write_data(void* items, size_t item_size, size_t item_count, void* ctx){
+    size_t data_size = item_count * item_size;
+    stringstream* buffer = reinterpret_cast<stringstream*>(ctx);
+    char* item = reinterpret_cast<char *>(items);
+    //buffer.write(items, data_size);
+    buffer->write(item, 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, 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 != 0){
+                cerr << curl_easy_strerror(res) << endl;
+                exit(1);
+            }
+        }
+        curl_easy_cleanup(curl);
+    return input_data(buffer, false);
+}
+
+
+
 int
 main(int argc, char* argv[])
 {
     curl_global_init(CURL_GLOBAL_ALL);
+    Input input;
+    /*
     if (argc > 1){
         CURL* curl = curl_easy_init();
         if(curl) {
@@ -52,9 +88,15 @@ main(int argc, char* argv[])
             }
         }
         curl_easy_cleanup(curl);
+    }*/
+    if (argc > 1){
+        input = download(argv[1]);
+    }
+    else{
+        input = input_data(cin, true);
     }
-    auto in = input_data(cin, true);
-    auto bins = make_histogram(in.numbers, in.bin_count);
+    //auto in = input_data(cin, true);
+    const auto bins = make_histogram(input.numbers, input.bin_count);
     show_histogram_svg(bins);
     return 0;
 }