.h -> .hpp for clearer ABI (non)compatibility

include/FileService.hpp

@@ -0,0 +1,17 @@
+#ifndef FILE_SERVICE_H
+#define FILE_SERVICE_H
+
+#include <string>
+#include <vector>
+
+class FileService {
+    public:
+    static bool doesNonEmptyFileExist(std::string);
+    static void emptyFile(std::string);
+    static void createOrOverwriteFile(std::string, std::string);
+    static void appendToFile(std::string, std::string);
+    static void deleteNthLine(std::string, int);
+    static std::vector<std::string> readLines(std::string);
+};
+
+#endif