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  • Is using the break statement bad practice?

    - by Lchi
    I've been told by professors and peers at my university that using the break statement is bad practice, but through my coursework haven't come up with a great reason why. Those who claim that it is bad say that it's a "get out of jail free card" and that you can always avoid using it. My guesses for why its considered bad would be that you could possibly skip some cleanup code after the break, or similarly exit some control structure in an inconsistent state. Is there any reason why using break is(n't) bad practice?

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  • diff between tables

    - by www.yegorov-p.ru
    I have two tables, with the same structure, for example: table "first' with columns 'a','b','c' and table 'second' with the same columns. How to find difference betweet those two tables? Of course, I can make some script on python, that will make set(a)-set(b), but I think there is some way to do it in mysql.

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  • error with string list in C#

    - by Chelsea_cole
    Same namespace: 2 forms. public class Account //frm1 { public string Username; public string Password; } public class ListAcc { public static List<Account> UserList; } private void button1_Click(object sender, EventArgs e) { List<Account> UserList = new List<Account>(); Account acc = new Account(); acc.Username = textBox1.Text; acc.Password = textBox2.Text; UserList.Add(acc); } private void button2_Click(object sender, EventArgs e) //frm2 { string p = frmDangky.ListAcc.UserList[0].Username; // null ->error string p = frmDangky.ListAcc.UserList[0].Password; // null ->error } Someone help me? :( why my string is NULL???????? The textBox is not empty... Thanks!

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  • C# Proxy, what is the best way to do this?

    - by Kin
    I'm writing a proxy using .NET and C#. It has a couple of functions that it needs to fulfill. I haven't done much Socket programming, and I am not sure the best way to go about it. Should I use Synchronous Sockets, Asynchronous sockets? Please help! It must... Accept Connections from the client on two different ports, and be able to receive data on both ports at the same time. When a connection is made on a port, it must immediately connect to the server, and start sending data as it receives it from the client to the server. Packets must be forwarded in the order they are received, exactly as they were received. It needs to be as low latency as possible. I don't need the ability for multiple clients to use the proxy, but it would be a nice feature if its easy to implement.

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  • Getting started with microcontroller programming

    - by Trix
    I'm a fairly good programmer, knowledgeable in C, C++, Python, Ruby and PHP. I'd like to get started with microcontroller programming. I do know nothing about this topic. Microcontrollers are minimal computers on little circuit boards, right? I'm pretty new to electronics too, do I need to be an expert in it to do stuff with microcontrollers? What can I do with them? Would e.g.: A Pacman or Tetris game on an LCD be possible and not too hard? Where should I start? Basically I want to program something really small I can then take with me. This is my only real goal. Are microcontrollers the right thing for this, or are there better solutions? I'd like to do this for fun and as a hobby, I don't want to become a professional in it.

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  • Initialize a Variable Again.

    - by SoulBeaver
    That may sound a little confusing. Basically, I have a function CCard newCard() { /* Used to store the string variables intermittantly */ std::stringstream ssPIN, ssBN; int picker1, picker2; int pin, bankNum; /* Choose 5 random variables, store them in stream */ for( int loop = 0; loop < 5; ++loop ) { picker1 = rand() % 8 + 1; picker2 = rand() % 8 + 1; ssPIN << picker1; ssBN << picker2; } /* Convert them */ ssPIN >> pin; ssBN >> bankNum; CCard card( pin, bankNum ); return card; } that creates a new CCard variable and returns it to the caller CCard card = newCard(); My teacher advised me that doing this is a violation of OOP principles and has to be put in the class. He told me to use this method as a constructor. Which I did: CCard::CCard() { m_Sperre = false; m_Guthaben = rand() % 1000; /* Work */ /* Convert them */ ssPIN >> m_Geheimzahl; ssBN >> m_Nummer; } All variables with m_ are member variables. However, the constructor works when I initialize the card normally CCard card(); at the start of the program. However, I also have a function, that is supposed to create a new card and return it to the user, this function is now broken. The original command: card = newCard(); isn't available anymore, and card = new CCard(); doesn't work. What other options do I have? I have a feeling using the constructor won't work, and that I probably should just create a class method newCard, but I want to see if it is somehow at all possible to do it the way the teacher wanted. This is creating a lot of headaches for me. I told the teacher that this is a stupid idea and not everything has to be classed in OOP. He has since told me that Java or C# don't allow code outside of classes, which sounds a little incredible. Not sure that you can do this in C++, especially when templated functions exist, or generic algorithms. Is it true that this would be bad code for OOP in C++ if I didn't force it into a class?

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  • Blackberry - Disable Save option in BasicEditField ??

    - by chethan
    I am using a basiceditfield to take input from the user to do some simple string search. But if i type a few letters and wish to go back without continuing the search, it automatically asks me whether to save the contents of the field. I don want this to happen. Can i in any way disable the "Changes made!-save-discard-cancel" option in basiceditfield(or any editfield for that matter)????please help!!!

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  • Looking to eventually build a smartphone app...

    - by Brian L
    Hi all- I'm a young, inexperienced programmer (I've had a year of Java, some MATLAB, and HTML/CSS in school) but I've decided that to get better, I'm making it my goal to produce a simple smartphone app of some kind this year- probably either webOS or Android since I'm on a PC and can't afford a Mac just to write an iPhone app. So my question is, where do I start? I've read the threads about How to Write for Android and such, but I'm not sure I have enough Java experience to just jump right in. And then there's webOS which is based on JavaScript, correct? I guess I'd just like some input from more experienced folks. I have some Barnes and Noble book credit I'm looking to get rid of too, so if there's a guide you think would be useful, feel free to request. tl;dr: Programming newbie ultimately wants to build a simple smartphone app. Where do I start?

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  • Efficiently generate a 16-character, alphanumeric string

    - by ensnare
    I'm looking for a very quick way to generate an alphanumeric unique id for a primary key in a table. Would something like this work? def genKey(): hash = hashlib.md5(RANDOM_NUMBER).digest().encode("base64") alnum_hash = re.sub(r'[^a-zA-Z0-9]', "", hash) return alnum_hash[:16] What would be a good way to generate random numbers? If I base it on microtime, I have to account for the possibility of several calls of genKey() at the same time from different instances. Or is there a better way to do all this? Thanks.

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  • mysqli and field types

    - by Mikk
    Hi, I'd like to know if there is a simple way to fetch data from mysql tables with "correct" data types? What i mean, if field type is for example INT or SMALLINT is it possible to pass those types directly to PHP as integers? I did some searching and found mysqli_fetch_fields, but for SMALLIT type is 2, for INT 3 and so on. It could be done that way, but it looks rather clumsy workaround. Is there any better way? I'm using PHP and mysqli. Thank you.

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  • QT4 Designer - Implement Widget

    - by MOnsDaR
    I'm currently trying to get into QT4 and figure out a workflow for myself. While trying to create a widget which allows the user to connect to a hostname:port some questions appeared. The widget itself contains a LineEdit for entering the hostname, a SpinBox for entering the port and a PushButton which should emit a connect(QString hostname, unsigned int port) signal. In QTDesigner I created the necessary Form. It is saved as a .ui-File. Now the big question is how could I implement the widget? Is there a place in QTDesigner where I could add my signal to the Widget? Where could I add custom Properties? I've learned in another tutorial, which showed how to create a Widget in C++, how signals, slots, Q_PROPERTIES etc are defined and added to the widget. But there is no sourcecode in QTDesigner. Another option would be to generate sourcecode using uic. But the header says, that another generate would overwrite any changes to the sourcefiles. So how can I create a QT-widget completely with my own signals, slots and properties by using the QTDesigner for creating the UI and not having to recode everything whenever the UI is changing. Is there some kind of Roundtrip-Engineering? If thats not possible: Whats the sense of creating a Widget with QTDesigner then?

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  • importing class and its function from another file

    - by user343934
    Hi everyone, I am having little problem with importing classes in python. My work flow goes like this index.py class Template: def header(): def body(): def form(): def footer(): display.py I want to call function header(), body() and footer () in my display.py page. Will anyone make me clear about this issue in python. Thanks for your concern.

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  • Data sources and NSTableView

    - by lampShade
    I know that table sources need a data source to hold the data that the tableview will display. Lets' say that I'm going to make my AppController be the data source of my tableview and that I make the connection in interface builder. My question is since my actual data is going to be stored in an array,let's call it myArray, when I set the data source in code should I do this [tableView setDataSource:myArray]; or this [tableView setDataSource:self]; I'm confused about this. setting the data source with the keyword "self" would set it to the AppController if I'm not mistaken.

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  • Restore previously serialized JFrame-object, how?

    - by elementz
    Hi all. I have managed to serialize my very basic GUI-object containing a JTextArea and a few buttons to a file 'test.ser'. Now, I would like to completely restore the previously saved state from 'test.ser', but seem to have a misconception of how to properly deserialize an objects state. The class MyFrame creates the JFrame and serializes it. public class MyFrame extends JFrame implements ActionListener { // Fields JTextArea textArea; String title; static MyFrame gui = new MyFrame(); private static final long serialVersionUID = 1125762532137824262L; /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub gui.run(); } // parameterless default contructor public MyFrame() { } // constructor with title public MyFrame(String title) { } // creates Frame and its Layout public void run() { JFrame frame = new JFrame(title); JPanel panel_01 = new JPanel(); JPanel panel_02 = new JPanel(); JTextArea textArea = new JTextArea(20, 22); textArea.setLineWrap(true); JScrollPane scrollPane = new JScrollPane(textArea); scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED); panel_01.add(scrollPane); // Buttons JButton saveButton = new JButton("Save"); saveButton.addActionListener(this); JButton loadButton = new JButton("Load"); loadButton.addActionListener(this); panel_02.add(loadButton); panel_02.add(saveButton); // Layout frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.getContentPane().add(BorderLayout.CENTER, panel_01); frame.getContentPane().add(BorderLayout.SOUTH, panel_02); frame.setSize(300, 400); frame.setVisible(true); } /* * */ public void serialize() { try { ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("test.ser")); oos.writeObject(gui); oos.close(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } } public void actionPerformed(ActionEvent ev) { System.out.println("Action received!"); gui.serialize(); } } Here I try to do the deserialization: public class Deserialize { static Deserialize ds; static MyFrame frame; public static void main(String[] args) { try { ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test.ser")); frame = (MyFrame) ois.readObject(); ois.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } Maybe somebody could point me into the direction where my misconception is? Thx in advance!

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  • Why do I get "mysql_query(): supplied argument is not a valid"

    - by Brian Ojeda
    Why do I get a "mysql_query(): supplied argument is not a valid" for the first... $r = mysql_query($q, $connection); In the following code... $bId = trim($_POST['bId']); $title = trim($_POST['title']); $story = trim($_POST['story']); $q = "SELECT * "; $q .= "FROM " . DB_NAME . ".`blog` "; $q .= "WHERE `blog`.`id` = {$bId}"; $r = mysql_query($q, $connection); //confirm_query($r); if (mysql_num_rows($r) == 1) { $q = "UPDATE " . DB_NAME . ".`blog` SET `title` = '{$title}', `story` = '{$story}' WHERE `id` = {$bId}"; $r = mysql_query($q, $connection); if (mysql_affected_rows() == 1) { //Successful $data['success'] = true; $date['errors'] = false; $date['message'] = "You are the Greatest!"; } else { //Fail $data['success'] = false; $data['error'] = true; $date['message'] = "You can't do it fool!"; } } I also get an "mysql_num_rows(): supplied argument is not a valid MySQL result resource" error too. Side notes: I am using 1&1 Hosting (worst hosting ever), custom .htaccess file with one line text to enable PHP 5.2 (only why with 1&1 Hosting).

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  • feeding input to a java process from a batch file

    - by YGL
    If I have a simple java program that processes lines of text from standard input, then I can run it with the following script: @Echo off java Test < file.txt pause exit The script redirects lines of input from a separate file. Is there a way that I can avoid having to use an extra file? Or is this the easiest way? Thanks.

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