code: добавлен параметр prompt

main.cpp

@@ -15,16 +15,20 @@ struct Input
     size_t bin_count{};
 };
 
-Input input_data(istream& stream)
+Input input_data(istream& stream, bool prompt)
 {
     size_t number_count;
+    if (prompt){
         cerr << "Enter number count:";
+    }
     stream >> number_count;
 
     Input in;
 
     in.numbers.resize(number_count);
+    if (prompt){
         cerr << "Enter numbers: ";
+    }
     for(size_t i = 0; i < number_count; i++)
         stream >> in.numbers[i];
 
@@ -37,7 +41,8 @@ Input input_data(istream& stream)
 
 int main()
 {
-    auto in = input_data(cin);
+    bool prompt = true;
+    auto in = input_data(cin, prompt);
 
     auto bins = make_histogram(in.numbers, in.bin_count);
   // show_histogram_svg_vertical(bins);