diff --git a/Lab01.cbp b/Lab01.cbp
index 88781ad..d25c7da 100644
--- a/Lab01.cbp
+++ b/Lab01.cbp
@@ -32,6 +32,7 @@
 			<Add option="-Wall" />
 			<Add option="-fexceptions" />
 		</Compiler>
+		<Unit filename="histogram.cpp" />
 		<Unit filename="main.cpp" />
 		<Extensions />
 	</Project>
diff --git a/histogram.cpp b/histogram.cpp
new file mode 100644
index 0000000..ebae521
--- /dev/null
+++ b/histogram.cpp
@@ -0,0 +1,45 @@
+#include "histogram.h"
+#include <vector>
+static void find_minmax(const std::vector <double> &numbers, double &min, double &max)
+{
+    min = numbers[0];
+    max = numbers[0];
+    for (double x : numbers)
+    {
+        if (x < min)
+        {
+            min = x;
+        }
+        else if (x > max)
+        {
+            max = x;
+        }
+    }
+}
+std::vector<std::size_t> make_histogram(const std::vector<double> &numbers, std::size_t bin_count)
+{
+    double min, max;
+    find_minmax(numbers, min, max);
+    double bin_size = (max - min) / bin_count;
+    std::vector <std::size_t> bins (bin_count);
+
+    for (std::size_t i = 0; i < numbers.size(); i++)
+    {
+        bool found = false;
+        for (std::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;
+}
diff --git a/histogram.h b/histogram.h
new file mode 100644
index 0000000..d6b10a3
--- /dev/null
+++ b/histogram.h
@@ -0,0 +1,9 @@
+#ifndef HISTOGRAM_H_INCLUDED
+#define HISTOGRAM_H_INCLUDED
+#include <vector>
+
+std::vector<size_t>
+make_histogram(const std::vector<double>& numbers, size_t bin_count);
+
+
+#endif // HISTOGRAM_H_INCLUDED
diff --git a/main.cpp b/main.cpp
index 6e40842..4e8bb0d 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,6 +1,6 @@
 #include <iostream>
 #include <vector>
-
+#include "histogram.h"
 using namespace std;
 struct Input
 {
@@ -26,51 +26,6 @@ input_data()
     return in;
 }
 void
-find_minmax(const vector<double> &numbers, double &min, double &max)
-{
-    min = numbers[0];
-    max = numbers[0];
-    for (double x : numbers)
-    {
-        if (x < min)
-        {
-            min = x;
-        }
-        else if (x > max)
-        {
-            max = x;
-        }
-    }
-}
-vector<size_t> make_histogram(const vector<double> &numbers, size_t bin_count)
-{
-    double min = numbers[0];
-    double max = numbers[0];
-    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(const vector <size_t> &bins)
 {
     const size_t SCREEN_WIDTH = 80;
@@ -130,7 +85,7 @@ show_histogram_text(const vector <size_t> &bins)
 int
 main()
 {
-    auto in = input_data();
+    Input in = input_data();
     auto bins = make_histogram(in.numbers, in.bin_count);
     show_histogram_text(bins);
 }