Using single quote for one character parameter in find_last_of method call

code/ObjExporter.cpp

@@ -125,7 +125,7 @@ std::string ObjExporter :: GetMaterialLibName()
 std::string ObjExporter :: GetMaterialLibFileName()
 {
     // Remove existing .obj file extention so that the final material file name will be fileName.mtl and not fileName.obj.mtl
-    size_t lastdot = filename.find_last_of(".");
+    size_t lastdot = filename.find_last_of('.');
     if (lastdot != std::string::npos)
         filename = filename.substr(0, lastdot);