diff --git a/Beginning C++ 17 source code/Examples/Chapter 12/Ex12_11/Ex12_11.cpp b/Beginning C++ 17 source code/Examples/Chapter 12/Ex12_11/Ex12_11.cpp
index d1c6f8a..44b55ac 100644
--- a/Beginning C++ 17 source code/Examples/Chapter 12/Ex12_11/Ex12_11.cpp	
+++ b/Beginning C++ 17 source code/Examples/Chapter 12/Ex12_11/Ex12_11.cpp	
@@ -3,7 +3,7 @@
 #include <memory>
 #include <cstdlib>                                 // For random number generator
 #include <ctime>                                   // For time function
-#include "Truckload.h"
+#include "Truckload.cpp"
 
 // Function to generate integral random box dimensions from 1 to max_size
 inline double random(double max_size)