static void Main() { var calc1 = new ScientificCalculator(); var calc2 = new ScientificCalculator(0, "x") { EndAngle = 360 }; ScientificCalculator calc3 = null; try { calc3 = new ScientificCalculator(); // do stuff } finally { if (calc3 != null) { calc3.Dispose(); } } using (var calc4 = new ScientificCalculator()) { // do stuff } Console.ReadKey(); }