private static void Main(string[] args) { var stack = new Stack(); stack.Push("111"); stack.Push("222"); WriteLine($"The length: {stack.Size()}"); WriteLine($"The top: {stack.Pop()}"); WriteLine($"The length: {stack.Size()}"); stack.Push("333"); stack.Clean(); WriteLine($"The length: {stack.Size()}"); if (!stack.IsEmpty()) { WriteLine($"The top: {stack.Pop()}"); } WriteLine(stack.Pop()); }