добавил .cpp и .h и изменил main.cpp

histogram.cpp

@@ -0,0 +1,52 @@
+#include <iostream>
+#include <vector>
+#include "histogram.h"
+using namespace std;
+
+void static find_minmax(const vector<double> &numbers, double &min, double &max)
+{
+    min = numbers[0];
+    max = numbers[0];
+    for(double number : numbers)
+    {
+        if(number < min)
+        {
+            min = number;
+        }
+        if(number > max)
+        {
+            max = number;
+        }
+    }
+    return;
+
+}
+
+std::vector<size_t> make_histogram(std::vector<double>& numbers, size_t bin_count)
+{
+
+    double min;
+    double max;
+    find_minmax (numbers, min, max);
+    double bin_size = (max - min) / bin_count;
+    vector<size_t> bins(bin_count);
+    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]++;
+                found = true;
+            }
+        }
+        if (!found)
+        {
+            bins[bin_count-1]++;
+        }
+    }
+    return bins;
+}

histogram.h

@@ -0,0 +1,7 @@
+#ifndef HISTOGRAM_H_INCLUDED
+#define HISTOGRAM_H_INCLUDED
+#include <vector>
+
+std::vector<size_t> make_histogram(std::vector<double>& numbers, size_t bin_count);
+
+#endif // HISTOGRAM_H_INCLUDED

main.cpp

@@ -1,6 +1,6 @@
 #include <iostream>
 #include <vector>
-
+#include "histogram.h"
 using namespace std;
 
 struct Input {
@@ -25,48 +25,8 @@ input_data(){
     return in;
 }
 
-void find_minmax(const vector<double> &numbers, double &min, double &max){
-    min = numbers[0];
-    max = numbers[0];
-    for(double number : numbers)
-    {
-        if(number < min)
-        {
-            min = number;
-        }
-        if(number > max)
-        {
-            max = number;
-        }
-    }
-    return;
-}
-vector<size_t> make_histogram (vector<double> numbers, size_t bin_count){
-    double min;
-    double max;
-    find_minmax (numbers, min, max);
-    double bin_size = (max - min) / bin_count;
-    vector<size_t> bins(bin_count);
-    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]++;
-                found = true;
-            }
-        }
-        if (!found)
-        {
-            bins[bin_count-1]++;
-        }
-    }
-    return bins;
-}
+
+
 void show_histogram_text(vector<size_t> bins, size_t bin_count){
     const size_t SCREEN_WIDTH = 80;
     const size_t MAX_ASTERISK = SCREEN_WIDTH - 3 - 1;