финальная версия с вариантом

main.cpp

@@ -75,16 +75,35 @@ download(const string& adress){
 int main(int argc, char* argv[])
 {
     curl_global_init(CURL_GLOBAL_ALL);
-     Input in;
+    string color = "base";
+    Input in;
     if (argc > 1) {
-        in = download(argv[1]);
-    } else {
+        for (size_t i = 0; i < argc; i += 1){
+            if (strcmp(argv[i], "-fill") == 0){
+                if (i - 1 < 1){
+                    in = download(argv[i + 2]);
+                    color = argv[i + 2];
+                }
+                else{
+                    if (i + 1 >= argc){
+                        cerr << "Error: please enter color";
+                        exit(1);
+                    }
+                    else{
+                        in = download(argv[i - 1]);
+                        color = argv[i + 1];
+                    }
+                }
+            }
+        }
+    }
+     else {
         in = input_data(cin, true);
     }
 
     auto bins = make_histogram(in.numbers, in.bin_count);
     auto borders = make_borders(in.numbers, in.bin_count);
-    show_histogram_svg(bins, borders, in.bin_count);
+    show_histogram_svg(bins, borders, in.bin_count, color);
     getch();
     return 0;
 }

svg.cpp

@@ -42,8 +42,7 @@ svg_rect(double x, double y, double width, double height, string stroke = "black
 
 
 void
-show_histogram_svg(const vector<size_t>& bins, const vector<double>& borders, size_t bin_count)
-{
+show_histogram_svg(const vector<size_t>& bins, const std::vector<double>& borders, size_t bin_count, string filling) {
     const auto IMAGE_WIDTH = 400;
     const auto IMAGE_HEIGHT = 300;
     const auto TEXT_LEFT = 20;
@@ -51,9 +50,8 @@ show_histogram_svg(const vector<size_t>& bins, const vector<double>& borders, si
     const auto TEXT_WIDTH = 50;
     const auto BIN_HEIGHT = 30;
     const auto BLOCK_WIDTH = 10;
-    const auto COLOUR1 = "black";
-    const auto COLOUR2 = "green";
     const auto MAX_WIDTH = IMAGE_WIDTH-TEXT_WIDTH;
+    vector <string> colors = {"red", "blue", "gold", "lime", "aqua", "green", "orange"};
     size_t border = 0;
     size_t number_of_blocks;
 
@@ -61,6 +59,8 @@ show_histogram_svg(const vector<size_t>& bins, const vector<double>& borders, si
     size_t max_bin = *max_element(bins.begin(), bins.end());
 
     double top = 0;
+    size_t paint_swicher = 0;
+    string color;
     double max_count = bins[0];
     for (size_t i = 0; i < bins.size(); i++)
     {
@@ -72,14 +72,23 @@ show_histogram_svg(const vector<size_t>& bins, const vector<double>& borders, si
 
     for (size_t bin : bins)
     {
+        if (filling != "base"){
+            color = filling;
+        }
+        else{
+            color = colors[paint_swicher];
+        }
         number_of_blocks = bin;
         if ((max_bin * BLOCK_WIDTH) > (IMAGE_WIDTH - TEXT_WIDTH)){
             number_of_blocks = ((IMAGE_WIDTH - TEXT_WIDTH)/10) * (static_cast<double>(bin) / max_bin);
         }
         const double bin_width = BLOCK_WIDTH * number_of_blocks;
         svg_text(TEXT_LEFT, top + TEXT_BASELINE, to_string(bin));
-        svg_rect(TEXT_WIDTH, top, bin_width, BIN_HEIGHT, COLOUR1, COLOUR2);
-        top += BIN_HEIGHT;
+        svg_rect(TEXT_WIDTH, top, bin_width, BIN_HEIGHT, "black", color);
+        paint_swicher += 1;
+        if (paint_swicher > 6){
+            paint_swicher = 0;
+        }
         if (border < bin_count - 1){
             top += BIN_HEIGHT;
             svg_text(TEXT_LEFT / 2, top + TEXT_BASELINE , to_string(borders[border]));

svg.h

@@ -3,9 +3,9 @@
 #include <vector>
 #include <iostream>
 #include <algorithm>
-
+#include <string>
 void
-show_histogram_svg(const std::vector<size_t>& bins,  const std::vector<double>& borders, size_t bin_count);
+show_histogram_svg(const std::vector<size_t>& bins,  const std::vector<double>& borders, size_t bin_count, std::string filling);
 
 
 #endif // SVG_H_INCLUDED