header: histogram

histogram.cpp

@@ -0,0 +1,37 @@
+#include "histogram.h"
+void
+find_minmax(const std::vector<double>& numbers, double& min, double& max){
+    min = numbers[0];
+    max = numbers[0];
+    for (double x: numbers){
+        if (min > x){
+            min = x;
+        }
+        if (max < x){
+            max = x;
+        }
+    }
+}
+
+std::vector<size_t>
+make_histogram(const std::vector<double>& numbers, size_t bin_count){
+    double min, max;
+    std::vector <size_t> bins(bin_count);
+    find_minmax(numbers, min, max);
+    double diff = (max - min) / bin_count;
+    for (double x: numbers){
+        bool found = false;
+        for (size_t j = 0;(j < bin_count - 1) && !found; j++){
+            auto lo = min + j * diff;
+            auto hi = min + (j + 1) * diff;
+            if ((lo <= x) && (hi > x)){
+                bins[j]++;
+                found = true;
+            }
+        }
+        if(!found){
+            bins[bin_count - 1]++;
+        }
+    }
+    return bins;
+}

histogram.h

@@ -0,0 +1,8 @@
+#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