Итоговый код

main.cpp

@@ -1,8 +1,12 @@
 #include <iostream>
+#include <sstream>
+#include <string>
 #include <vector>
+#include <curl/curl.h>
 #include "histogram.h"
 #include "text.h"
 #include "svg.h"
+
 using namespace std;
 
 struct Input {
@@ -10,30 +14,72 @@ struct Input {
     size_t bin_count{};
 };
 
-Input
-input_data() {
-    cerr << "Enter number count, numbers and bin count: ";
-
-    size_t number_count;
-    cin >> number_count;
-
-    Input in;
-    in.numbers.resize(number_count);
-
-    for (size_t i = 0; i < number_count; i++) {
-        cin >> in.numbers[i];
+Input input_data(istream& in, bool prompt) {
+    if (prompt) {
+        cerr << "Enter number count, numbers and bin count: ";
     }
 
-    cin >> in.bin_count;
+    size_t number_count;
+    in >> number_count;
 
-    return in;
+    Input input;
+    input.numbers.resize(number_count);
+
+    for (size_t i = 0; i < number_count; i++) {
+        in >> input.numbers[i];
+    }
+
+    in >> input.bin_count;
+
+    return input;
 }
 
+size_t write_data(void* items, size_t item_size, size_t item_count, void* ctx) {
+    size_t data_size = item_size * item_count;
 
-int
-main() {
-    auto in = input_data();
-    auto bins = make_histogram(in.numbers, in.bin_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) {
+        curl_easy_setopt(curl, CURLOPT_URL, address.c_str());
+
+        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
+        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &buffer);
+
+        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);
+    }
+
+    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);
+    }
+
+    const auto bins = make_histogram(input.numbers, input.bin_count);
     show_histogram_svg(bins);
 
     return 0;