HeadFirst | HeadFirst设计模式一书中代码案例的PHP版本

In the Head First Design Patterns book, the authors describe using an iterator to traverse over composite data structures. They provide some sample code which, when executed, prints out a series of menu items stored within the composite. However, if you try to call the iterator more than once, it no longer works as expected and won't produce any results. The following code appears to be causing the problem:

I'm trying to follow along with my javascript book "headfirst javascript programming"....

the assignment is to make a simplified battleship game. It was working until I added more code... Now the prompt is not showing. Im sure im doing something wrong with the curly brackets. I just want the prompt "Ready, aim, fire! (enter a number from 0-6):" to appear when launching the browser and for it to respond to numerical inputs.

Can anyone quickly tell me why im screwing up? thank you! here is my simple code --->>>

Reading Java Headfirst found this example pls if someone can help me understand.

I'm trying to make a battleship game, and this is the part where the players set their boards. When the second player to set the board makes theirs, the first player's board becomes the same as the second player's (when playing the game guessing the locations of that board are misses though, but that's another problem that will hopefully be fixed once this is). For example if I set the first player's ships as being at A1 A2 A3, B1 B2 B3, and C1 C2 C3, then set the second player's ships as D1 D2 D3, E1 E2 E3, and F1 F2 F3, when both lists of ships are printed out I get D1 D2 D3, E1 E2 E3, and F1 F2 F3 for both ships. I've found other questions on here with the same problem, but they always had the problem because they didn't make new lists every time, which I do (at least I'm pretty sure I do), so I can't find where my problem is. Here is the entire main game class, the GetShipLocations, SetShipLocations, and PlayersMakeTheirBoards, functions are what are giving me problems.

So I have what is potentially a dumb question regarding MS Access. If I wish to make a form which can be used to populate multiple tables in a relational database, must these other tables be represented by subforms? From what I understand, you could manually change the RecordSource of the main form to include the rare one-to-one relationship, but is there any way such a thing would work for a one-to-many or a many-to-many relationship?

On its face, it seems to me that there's no way this would be possible-- after all, how would Access know how to arrange the multiple elements in a one-to-many relationship on the page?

I'm 90% sure the answer to this is "No, you must use subforms when designing a form which represents a relational model, unless it only contained one-to-one relationships", but I still feel I would be remiss if I didn't double-check this, since I basically jumped headfirst into Access development with no prior experience, and I want to make sure I'm not making an obvious mistake.

I have tried hard but can't resolve the problem. The error that comes up is:

I've been learning about tabs and ActionBar in Android. I can't get my head around it. what is the difference between a TabLayout and an AppBarLayout? why you put Toolbar tag inside AppBarLayout? what programmers want to achieve doing this?

the following xml file is an example from HeadFirst Android. if possible, consider answering my Qs by explaining what is happening here.

I'm attempting to iterate through the fields in an Object (using reflection, via FieldInfo) and dump their values... and just fell headfirst into a C# vs Java trap.

The problem I'm running into is the fact that

1. FieldInfo.GetValue(srcObject) can return an int[] (or some other array of primitive values) as an Object

2. c# doesn't allow you to cast an Object holding an int[] to Object[]

So... if

System.Object val = fieldInfo.GetValue(srcObject)

and

val.GetType().IsArray returns 'True'

... what do I need to do to

1. Recognize at runtime that 'val' is "an Object that's an array, but not an array of Objects"?

2. transform 'val' into an array of printable values that I can iterate through?

I'm beginning to teach myself JavaScript via HeadFirst JavaScript, and I've hit a little bit of a snag. The chapter I'm doing focuses on handling input of data into forms. When I try to use the updateOrder() function, the parseInt() returns NaN, but the alert statements I've put in print the correct values. When I substitute "0" for "" in the value parts of the HTML code, I then get the correct behavior. This leads me to believe that a null character is being prepended to the input.

Update: It's late, and I should know better than to be typing code right now. I believe I have fixed all of the typos, and the code is as I have it in my sandbox run. I also want to than @imEnCoded for the edit contribution. Now that the typos are fixed, the original problem I posted about should present correctly.

My questions are:

• Am I doing something wrong (Minus some formatting changes, my code is exactly as how it is in the book)?

• Is there any way to get around this? I've seen one post on here that suggests using regular expressions to filter out any before characters, but I was kind of hoping for something cleaner.

For brevity, I've only included what I've determined to be the troublesome code here, but I will link the full solution code too.

Full HTML and JS for solution is here

The JavaScript part: