diff --git a/histogram.cpp b/histogram.cpp
index 344f24d..d7e5196 100644
--- a/histogram.cpp
+++ b/histogram.cpp
@@ -5,14 +5,19 @@
 using namespace std;
 
 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;
+    if (numbers.size() == 0){
+        min = 0;
+        max = 0;
+    } else {
+        min = numbers[0];
+        max = numbers[0];
+        for (double x : numbers) {
+            if (x < min) {
+                min = x;
+            }
+            else if (x > max) {
+                max = x;
+            }
         }
     }
 }
diff --git a/histogram_internal.h b/histogram_internal.h
index 3ea054e..630e711 100644
--- a/histogram_internal.h
+++ b/histogram_internal.h
@@ -3,6 +3,6 @@
 
 #include <vector>
 
-void find_minmax(const std::vector<double> &numbers, double &min, double &max)
+void find_minmax(const std::vector<double> &numbers, double &min, double &max);
 
 #endif // HISTOGRAM_INTERNAL_H_INCLUDED