final code

main.cpp

@@ -4,6 +4,8 @@
 #include "text.h"
 #include "svg.h"
 #include <curl/curl.h>
+#include <sstream>
+#include <string>
 
 using namespace std;
 
@@ -35,20 +37,47 @@ Input input_data(istream& inx, bool prompt)
     return in;
 }
 
-int main()
-{
-    curl_global_init(CURL_GLOBAL_ALL);
+size_t write_data(void* items, size_t item_size, size_t item_count, void* ctx) {
+    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;
+}
 
-    bool prompt = true;
-    auto in = input_data(cin, prompt);
+Input
+download(const string& address) {
+    stringstream buffer;
+    CURL* curl = curl_easy_init();
+    if (curl) {
+        curl_easy_setopt(curl, CURLOPT_URL, address.c_str());
 
-    auto bins = make_histogram(in.numbers, in.bin_count);
+        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
+        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &buffer);
 
-    double min, max;
+        CURLcode res = curl_easy_perform(curl);
+        if (res != CURLE_OK) {
+            cerr << "cURL error: " << curl_easy_strerror(res) << endl;
+            curl_easy_cleanup(curl);
+            exit(1);
+        }
+        curl_easy_cleanup(curl);
+    } else {
+        cerr << "curl_easy_init() failed" << endl;
+        exit(1);
+    }
 
-    double bin_size = (max - min) / in.bin_count;
+    return input_data(buffer, false);
+}
 
-    show_histogram_svg(bins);
+int
+main(int argc, char* argv[]) {
+    Input input;
+    if (argc > 1) {
+        input = download(argv[1]);
+    } else {
+        input = input_data(cin, true);
+    }
 
-    return 0;
+    const auto bins = make_histogram(input.numbers, input.bin_count);
+    show_histogram_svg(bins);
 }