diff --git a/cmake/example_project/example.h b/cmake/example_project/example.h
index 47b9a0aa2..eea1e13a5 100644
--- a/cmake/example_project/example.h
+++ b/cmake/example_project/example.h
@@ -20,6 +20,7 @@
 
 namespace example {
 
+#include <example/PrintExamples.h>
 class PrintExamples {
   void sayHello() const;
   void sayGoodbye() const;
diff --git a/cmake/example_project/example/PrintExamples.h b/cmake/example_project/example/PrintExamples.h
index b151dfbc7..25d4dd8cb 100644
--- a/cmake/example_project/example/PrintExamples.h
+++ b/cmake/example_project/example/PrintExamples.h
@@ -17,6 +17,7 @@
 
 #pragma once
 
+#include <iostream>
 #include <string>
 
 namespace example {