static void CalculateResidentsMoneySpent(ResidentsList residentsList, UtilitiesList utilitiesList) { for (residentsList.StartOfList(); residentsList.Contains(); residentsList.NextListNode()) { for (utilitiesList.StartOfList(); utilitiesList.Contains(); utilitiesList.NextListNode()) { residentsList.CalculateMoneySpent(utilitiesList.GetData()); } } }