разбила код на подпрограммы

main.cpp

@@ -2,71 +2,96 @@
 #include <vector>
 using namespace std;
 
-int main()
-{
-    size_t number_count, bin_count;
-    const size_t SCREEN_WIDTH = 80;
-    const size_t MAX_ASTERISK = SCREEN_WIDTH - 3 - 1;
+struct Input {
+    vector<double> numbers;
+    size_t bin_count{};
+};
 
+Input
+input_data() {
+    cerr << "Enter number count, numbers and bin count: ";
 
-    cerr << "Enter number count: ";
+    size_t number_count;
     cin >> number_count;
 
-    vector<double> numbers(number_count);
+    Input in;
+    in.numbers.resize(number_count);
 
-    cerr <<"Enter the numbers: ";
-    for (size_t i=0; i< number_count; i++) {
-        cin >> numbers[i];
+    for (size_t i = 0; i < number_count; i++) {
+        cin >> in.numbers[i];
     }
-    cerr << "Enter bin count: ";
-    cin >> bin_count;
 
-    vector<size_t> bins(bin_count);
+    cin >> in.bin_count;
+
+    return in;
+}
+
+void
+find_minmax(const vector<double>& numbers, double& min, double& max) {
+    min = numbers[0];
+    max = numbers[0];
 
-    double min = numbers[0];
-    double max = numbers[0];
     for (double x : numbers) {
         if (x < min) {
             min = x;
-            }
-            else if (x > max) {
+        } else if (x > max) {
             max = x;
         }
     }
+}
 
-    double bin_size = (max - min) / bin_count;
+vector<size_t>
+make_histogram(const vector<double>& numbers, size_t bin_count) {
+    vector<size_t> bins(bin_count, 0);
 
-    size_t max_count = 0;
+    double min, max;
+    find_minmax(numbers, min, max);
 
-    for (size_t i = 0; i < number_count; i++) {
+    double bin_size = (max - min) / bin_count;
+    if (bin_size == 0) {
+        bin_size = 1;
+    }
+
+    for (size_t i = 0; i < numbers.size(); i++) {
         bool found = false;
         for (size_t j = 0; (j < bin_count - 1) && !found; j++) {
             auto lo = min + j * bin_size;
             auto hi = min + (j + 1) * bin_size;
             if ((lo <= numbers[i]) && (numbers[i] < hi)) {
                 bins[j]++;
-            if (bins[j] > max_count) {
-                    max_count = bins[j];
-                }
                 found = true;
             }
         }
         if (!found) {
             bins[bin_count - 1]++;
-         if (bins[bin_count - 1] > max_count) {
-                max_count = bins[bin_count - 1];
         }
     }
+
+    return bins;
 }
- for (size_t i = 0; i < bin_count; i++) {
+
+void
+show_histogram_text(const vector<size_t>& bins, size_t screen_width = 80) {
+    const size_t MAX_ASTERISK = screen_width - 3 - 1;
+
+    size_t max_count = 0;
+    for (size_t count : bins) {
+        if (count > max_count) {
+            max_count = count;
+        }
+    }
+
+    for (size_t i = 0; i < bins.size(); i++) {
         size_t height = 0;
 
         if (max_count > MAX_ASTERISK) {
-            height = static_cast<size_t>(MAX_ASTERISK * static_cast<double>(bins[i]) / max_count);
-        }
-         else {
+            height = static_cast<size_t>(
+                MAX_ASTERISK * static_cast<double>(bins[i]) / max_count
+            );
+        } else {
             height = bins[i];
         }
+
         if (bins[i] < 10) {
             cout << "  " << bins[i] << "|";
         } else if (bins[i] < 100) {
@@ -74,11 +99,19 @@ int main()
         } else {
             cout << bins[i] << "|";
         }
+
         for (size_t j = 0; j < height; j++) {
             cout << "*";
         }
         cout << endl;
     }
+}
 
+int
+main() {
+    auto in = input_data();
+    auto bins = make_histogram(in.numbers, in.bin_count);
+    show_histogram_text(bins);
 
-    }
+    return 0;
+}