alphabetically sort list of files in a dir

SystemToolkit.cpp

@@ -4,6 +4,7 @@
 #include <fstream>
 #include <iomanip>
 #include <chrono>
+#include <algorithm>
 
 using namespace std;
 
@@ -301,6 +302,8 @@ list<string> SystemToolkit::list_directory(const string& path, const string& fil
         closedir (dir);
     }
 
+    ls.sort();
+
     return ls;
 }