diff --git a/source/cli.cpp b/source/cli.cpp
index 6b5e24f..487039b 100644
--- a/source/cli.cpp
+++ b/source/cli.cpp
@@ -1,6 +1,6 @@
-#include "cli.h"
+#include "cli.hpp"
 
-#include "exit_values.h"
+#include "exit_values.hpp"
 
 #include <getopt.h>
 #include <stdio.h>
diff --git a/source/cli.h b/source/cli.hpp
similarity index 100%
rename from source/cli.h
rename to source/cli.hpp
diff --git a/source/csml.l b/source/csml.l
index 6060375..ee29ba9 100644
--- a/source/csml.l
+++ b/source/csml.l
@@ -1,5 +1,5 @@
 %{
-#include "scanner.h"
+#include "scanner.hpp"
 
 #include <stdio.h>
 #include <stack>
diff --git a/source/exit_values.h b/source/exit_values.hpp
similarity index 100%
rename from source/exit_values.h
rename to source/exit_values.hpp
diff --git a/source/main.cpp b/source/main.cpp
index 2c58340..e6c41d2 100644
--- a/source/main.cpp
+++ b/source/main.cpp
@@ -7,8 +7,13 @@
 #include <string>
 #include <map>
 
-#include "cli.h"
-#include "exit_values.h"
+// uint32_t a(3084);
+// std::wstring_convert<std::codecvt_utf8<char32_t>, char32_t> conv1;
+// std::string u8str = conv1.to_bytes(a);
+// std::cout << "UTF-8 conversion produced " << u8str.size() << " bytes:\n";
+
+#include "cli.hpp"
+#include "exit_values.hpp"
 
 #define DECLARE_LEXER(x)       \
 	extern FILE * x ## in;     \
diff --git a/source/scanner.h b/source/scanner.hpp
similarity index 100%
rename from source/scanner.h
rename to source/scanner.hpp
diff --git a/source/xml.l b/source/xml.l
index 3bfd32b..3862764 100644
--- a/source/xml.l
+++ b/source/xml.l
@@ -1,5 +1,5 @@
 %{
-#include "scanner.h"
+#include "scanner.hpp"
 
 #include <stdio.h>