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  • Design pattern for cost calculator app?

    - by Anders Svensson
    Hi, I have a problem that I’ve tried to get help for before, but I wasn’t able to solve it then, so I’m trying to simplify the problem now to see if I can get some more concrete help with this because it is driving me crazy… Basically, I have a working (more complex) version of this application, which is a project cost calculator. But because I am at the same time trying to learn to design my applications better, I would like some input on how I could improve this design. Basically the main thing I want is input on the conditionals that (here) appear repeated in two places. The suggestions I got before was to use the strategy pattern or factory pattern. I also know about the Martin Fowler book with the suggestion to Refactor conditional with polymorphism. I understand that principle in his simpler example. But how can I do either of these things here (if any would be suitable)? The way I see it, the calculation is dependent on a couple of conditions: 1. What kind of service is it, writing or analysis? 2. Is the project small, medium or large? (Please note that there may be other parameters as well, equally different, such as “are the products new or previously existing?” So such parameters should be possible to add, but I tried to keep the example simple with only two parameters to be able to get concrete help) So refactoring with polymorphism would imply creating a number of subclasses, which I already have for the first condition (type of service), and should I really create more subclasses for the second condition as well (size)? What would that become, AnalysisSmall, AnalysisMedium, AnalysisLarge, WritingSmall, etc…??? No, I know that’s not good, I just don’t see how to work with that pattern anyway else? I see the same problem basically for the suggestions of using the strategy pattern (and the factory pattern as I see it would just be a helper to achieve the polymorphism above). So please, if anyone has concrete suggestions as to how to design these classes the best way I would be really grateful! Please also consider whether I have chosen the objects correctly too, or if they need to be redesigned. (Responses like "you should consider the factory pattern" will obviously not be helpful... I've already been down that road and I'm stumped at precisely how in this case) Regards, Anders The code (very simplified, don’t mind the fact that I’m using strings instead of enums, not using a config file for data etc, that will be done as necessary in the real application once I get the hang of these design problems): public abstract class Service { protected Dictionary<string, int> _hours; protected const int SMALL = 2; protected const int MEDIUM = 8; public int NumberOfProducts { get; set; } public abstract int GetHours(); } public class Writing : Service { public Writing(int numberOfProducts) { NumberOfProducts = numberOfProducts; _hours = new Dictionary<string, int> { { "small", 125 }, { "medium", 100 }, { "large", 60 } }; } public override int GetHours() { if (NumberOfProducts <= SMALL) return _hours["small"] * NumberOfProducts; if (NumberOfProducts <= MEDIUM) return (_hours["small"] * SMALL) + (_hours["medium"] * (NumberOfProducts - SMALL)); return (_hours["small"] * SMALL) + (_hours["medium"] * (MEDIUM - SMALL)) + (_hours["large"] * (NumberOfProducts - MEDIUM)); } } public class Analysis : Service { public Analysis(int numberOfProducts) { NumberOfProducts = numberOfProducts; _hours = new Dictionary<string, int> { { "small", 56 }, { "medium", 104 }, { "large", 200 } }; } public override int GetHours() { if (NumberOfProducts <= SMALL) return _hours["small"]; if (NumberOfProducts <= MEDIUM) return _hours["medium"]; return _hours["large"]; } } public partial class Form1 : Form { public Form1() { InitializeComponent(); List<int> quantities = new List<int>(); for (int i = 0; i < 100; i++) { quantities.Add(i); } comboBoxNumberOfProducts.DataSource = quantities; } private void comboBoxNumberOfProducts_SelectedIndexChanged(object sender, EventArgs e) { Service writing = new Writing((int) comboBoxNumberOfProducts.SelectedItem); Service analysis = new Analysis((int) comboBoxNumberOfProducts.SelectedItem); labelWriterHours.Text = writing.GetHours().ToString(); labelAnalysisHours.Text = analysis.GetHours().ToString(); } }

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  • Dereferencing pointers without pointing them at a variable

    - by Miguel
    I'm having trouble understanding how some pointers work. I always thought that when you created a pointer variable (p), you couldn't deference and assign (*p = value) unless you either malloc'd space for it (p = malloc(x)), or set it to the address of another variable (p = &a) However in this code, the first assignment works consistently, while the last one causes a segfault: typedef struct { int value; } test_struct; int main(void) { //This works int* colin; *colin = 5; //This never works test_struct* carter; carter->value = 5; } Why does the first one work when colin isn't pointing at any spare memory? And why does the 2nd never work? I'm writing this in C, but people with C++ knowledge should be able to answer this as well.

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  • Passing Boost uBLAS matrices to OpenGL shader

    - by AJM
    I'm writing an OpenGL program where I compute my own matrices and pass them to shaders. I want to use Boost's uBLAS library for the matrices, but I have little idea how to get a uBLAS matrix into OpenGL's shader uniform functions. matrix<GLfloat, column_major> projection(4, 4); // Fill matrix ... GLuint projectionU = glGetUniformLocation(shaderProgram, "projection"); glUniformMatrix4fv(projectionU, 1, 0, (GLfloat *)... Um ...); Trying to cast the matrix to a GLfloat pointer causes an invalid cast error on compile.

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  • Throwing Exception in CTOR and Smart Pointers

    - by David Relihan
    Is it OK to have the following code in my constructor to load an XML document into a member variable - throwing to caller if there are any problems: MSXML2::IXMLDOMDocumentPtr m_docPtr; //member Configuration() { try { HRESULT hr = m_docPtr.CreateInstance(__uuidof(MSXML2::DOMDocument40)); if ( SUCCEEDED(hr)) { m_docPtr->loadXML(CreateXML()); } else { //throw exception to caller } } catch(...) { //throw exception to caller } } Based on Scott Myers RAII implementations in More Effective C++ I believe I am alright in just allowing exceptions to be thrown from CTOR as I am using a smart pointer(IXMLDOMDocumentPtr). Let me know what you think....

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  • How to send large objects using boost::asio

    - by Max
    Good day. I'm receiving a large objects via the net using boost::asio. And I have a code: for (int i = 1; i <= num_packets; i++) boost::asio::async_read(socket_, boost::asio::buffer(Obj + packet_size * (i - 1), packet_size), boost::bind(...)); Where My_Class * Obj. I'm in doubt if that approach possible (because i have a pointer to an object here)? Or how it would be better to receive this object using packets of fixed size in bytes? Thanks in advance.

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  • Delphi - Using DeviceIoControl passing IOCTL_DISK_GET_LENGTH_INFO to get flash media physical size (Not Partition)

    - by SuicideClutchX2
    Alright this is the result of a couple of other questions. It appears I was doing something wrong with the suggestions and at this point have come up with an error when using the suggested API to get the media size. Those new to my problem I am working at the physical disk level, not within the confines of a partition or file system. Here is the pastebin code for the main unit (Delphi 2009) - http://clutchx2.pastebin.com/iMnq8kSx Here is the application source and executable with a form built to output the status of whats going on - http://www.mediafire.com/?js8e6ci8zrjq0de Its probably easier to use the download, unless your just looking for problems within the code. I will also paste the code here. unit Main; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TfrmMain = class(TForm) edtDrive: TEdit; lblDrive: TLabel; btnMethod1: TButton; btnMethod2: TButton; lblSpace: TLabel; edtSpace: TEdit; lblFail: TLabel; edtFail: TEdit; lblError: TLabel; edtError: TEdit; procedure btnMethod1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; TDiskExtent = record DiskNumber: Cardinal; StartingOffset: Int64; ExtentLength: Int64; end; DISK_EXTENT = TDiskExtent; PDiskExtent = ^TDiskExtent; TVolumeDiskExtents = record NumberOfDiskExtents: Cardinal; Extents: array[0..0] of TDiskExtent; end; VOLUME_DISK_EXTENTS = TVolumeDiskExtents; PVolumeDiskExtents = ^TVolumeDiskExtents; var frmMain: TfrmMain; const FILE_DEVICE_DISK = $00000007; METHOD_BUFFERED = 0; FILE_ANY_ACCESS = 0; IOCTL_DISK_BASE = FILE_DEVICE_DISK; IOCTL_VOLUME_BASE = DWORD('V'); IOCTL_DISK_GET_LENGTH_INFO = $80070017; IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS = ((IOCTL_VOLUME_BASE shl 16) or (FILE_ANY_ACCESS shl 14) or (0 shl 2) or METHOD_BUFFERED); implementation {$R *.dfm} function GetLD(Drive: Char): Cardinal; var Buffer : String; begin Buffer := Format('\\.\%s:',[Drive]); Result := CreateFile(PChar(Buffer),GENERIC_READ Or GENERIC_WRITE,FILE_SHARE_READ,nil,OPEN_EXISTING,0,0); If Result = INVALID_HANDLE_VALUE Then begin Result := CreateFile(PChar(Buffer),GENERIC_READ,FILE_SHARE_READ,nil,OPEN_EXISTING,0,0); end; end; function GetPD(Drive: Byte): Cardinal; var Buffer : String; begin If Drive = 0 Then begin Result := INVALID_HANDLE_VALUE; Exit; end; Buffer := Format('\\.\PHYSICALDRIVE%d',[Drive]); Result := CreateFile(PChar(Buffer),GENERIC_READ Or GENERIC_WRITE,FILE_SHARE_READ,nil,OPEN_EXISTING,0,0); If Result = INVALID_HANDLE_VALUE Then begin Result := CreateFile(PChar(Buffer),GENERIC_READ,FILE_SHARE_READ,nil,OPEN_EXISTING,0,0); end; end; function GetPhysicalDiskNumber(Drive: Char): Byte; var LD : DWORD; DiskExtents : PVolumeDiskExtents; DiskExtent : TDiskExtent; BytesReturned : Cardinal; begin Result := 0; LD := GetLD(Drive); If LD = INVALID_HANDLE_VALUE Then Exit; Try DiskExtents := AllocMem(Max_Path); DeviceIOControl(LD,IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS,nil,0,DiskExtents,Max_Path,BytesReturned,nil); If DiskExtents^.NumberOfDiskExtents > 0 Then begin DiskExtent := DiskExtents^.Extents[0]; Result := DiskExtent.DiskNumber; end; Finally CloseHandle(LD); end; end; procedure TfrmMain.btnMethod1Click(Sender: TObject); var PD : DWORD; CardSize: Int64; BytesReturned: DWORD; CallSuccess: Boolean; begin PD := GetPD(GetPhysicalDiskNumber(edtDrive.Text[1])); If PD = INVALID_HANDLE_VALUE Then Begin ShowMessage('Invalid Physical Disk Handle'); Exit; End; CallSuccess := DeviceIoControl(PD, IOCTL_DISK_GET_LENGTH_INFO, nil, 0, @CardSize, SizeOf(CardSize), BytesReturned, nil); if not CallSuccess then begin edtError.Text := IntToStr(GetLastError()); edtFail.Text := 'True'; end else edtFail.Text := 'False'; CloseHandle(PD); end; end. I placed a second method button on the form so I can write a different set of code into the app if I feel like it. Only minimal error handling and safeguards are there is nothing that wasn't necessary for debugging this via source. I tried this on a Sony Memory Stick using a PSP as the reader because I cant find the adapter for using a duo in my machine. The target is an MS and half of my users use a PSP for a reader half dont. However this should work fine on SD cards and that is a secondary target for my work as well. I tried this on a usb memory card reader and several SD cards. Now that I have fixed my attempt I get an error returned. 50 ERROR_NOT_SUPPORTED The request is not supported. I have found an application that uses this API as well as alot of related functions for what I am trying todo. I am getting ready to look into it the application is called DriveImage and its source is here - http://sourceforge.net/projects/diskimage/ The only thing I have really noticed from that application is there use of TFileStream and using that to get a handle on the physical disk.

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  • Help understanding some OpenGL stuff

    - by shinjuo
    I am working with some code to create a triangle that moves with arrow keys. I want to create a second object that moves independently. This is where I am having trouble, I have created the second actor, but cannot get it to move. There is too much code to post it all so I will just post a little and see if anyone can help at all. ogl_test.cpp #include "platform.h" #include "srt/scheduler.h" #include "model.h" #include "controller.h" #include "model_module.h" #include "graphics_module.h" class blob : public actor { public: blob(float x, float y) : actor(math::vector2f(x, y)) { } void render() { transform(); glBegin(GL_TRIANGLES); glVertex3f(0.25f, 0.0f, -5.0f); glVertex3f(-.5f, 0.25f, -5.0f); glVertex3f(-.5f, -0.25f, -5.0f); glEnd(); end_transform(); } void update(controller& c, float dt) { if (c.left_key) { rho += pi / 9.0f * dt; c.left_key = false; } if (c.right_key) { rho -= pi / 9.0f * dt; c.right_key = false; } if (c.up_key) { v += .1f * dt; c.up_key = false; } if (c.down_key) { v -= .1f * dt; if (v < 0.0) { v = 0.0; } c.down_key = false; } actor::update(c, dt); } }; class enemyOne : public actor { public: enemyOne(float x, float y) : actor(math::vector2f(x, y)) { } void render() { transform(); glBegin(GL_TRIANGLES); glVertex3f(0.25f, 0.0f, -5.0f); glVertex3f(-.5f, 0.25f, -5.0f); glVertex3f(-.5f, -0.25f, -5.0f); glEnd(); end_transform(); } void update(controller& c, float dt) { if (c.left_key) { rho += pi / 9.0f * dt; c.left_key = false; } if (c.right_key) { rho -= pi / 9.0f * dt; c.right_key = false; } if (c.up_key) { v += .1f * dt; c.up_key = false; } if (c.down_key) { v -= .1f * dt; if (v < 0.0) { v = 0.0; } c.down_key = false; } actor::update(c, dt); } }; int APIENTRY WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, char* lpCmdLine, int nCmdShow ) { model m; controller control(m); srt::scheduler scheduler(33); srt::frame* model_frame = new srt::frame(scheduler.timer(), 0, 1, 2); srt::frame* render_frame = new srt::frame(scheduler.timer(), 1, 1, 2); model_frame->add(new model_module(m, control)); render_frame->add(new graphics_module(m)); scheduler.add(model_frame); scheduler.add(render_frame); blob* prime = new blob(0.0f, 0.0f); m.add(prime); m.set_prime(prime); enemyOne* primeTwo = new enemyOne(2.0f, 0.0f); m.add(primeTwo); m.set_prime(primeTwo); scheduler.start(); control.start(); return 0; } model.h #include <vector> #include "vec.h" const double pi = 3.14159265358979323; class controller; using math::vector2f; class actor { public: vector2f P; float theta; float v; float rho; actor(const vector2f& init_location) : P(init_location), rho(0.0), v(0.0), theta(0.0) { } virtual void render() = 0; virtual void update(controller&, float dt) { float v1 = v; float theta1 = theta + rho * dt; vector2f P1 = P + v1 * vector2f(cos(theta1), sin(theta1)); if (P1.x < -4.5f || P1.x > 4.5f) { P1.x = -P1.x; } if (P1.y < -4.5f || P1.y > 4.5f) { P1.y = -P1.y; } v = v1; theta = theta1; P = P1; } protected: void transform() { glPushMatrix(); glTranslatef(P.x, P.y, 0.0f); glRotatef(theta * 180.0f / pi, 0.0f, 0.0f, 1.0f); //Rotate about the z-axis } void end_transform() { glPopMatrix(); } }; class model { private: typedef std::vector<actor*> actor_vector; actor_vector actors; public: actor* _prime; model() { } void add(actor* a) { actors.push_back(a); } void set_prime(actor* a) { _prime = a; } void update(controller& control, float dt) { for (actor_vector::iterator i = actors.begin(); i != actors.end(); ++i) { (*i)->update(control, dt); } } void render() { for (actor_vector::iterator i = actors.begin(); i != actors.end(); ++i) { (*i)->render(); } } };

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  • How to use ORDER BY, LOWER .. in SQL SERVER 2008 with non-unicode languages

    - by hgulyan
    Hi, The question is about Armenian. I'm using sql server 2005, collation SQL_Latin1_General_CP1_CI_AS, data mostly is in Armenian and we can't use unicode. I tested on ms sql 2008 with a windows collation for armenian language ( Cyrillic_General_100_ ), I have found here, ( http://msdn.microsoft.com/en-us/library/ms188046.aspx ) but it didn't help. I have a function, that orders hex values and lower function, which takes each char in string and covnerts it to it's lower form, but it's not acceptable solution, it works really slow, calling that functions on every column of a huge table. Is there any solution for this issue not using unicode and working with hex values manually?

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  • Why protected superclass member cannot be accessed in a subclass function when passed as an argument

    - by KNoodles
    I get a compile error, which I'm slightly confused about. This is on VS2003. error C2248: 'A::y' : cannot access protected member declared in class 'A' class A { public: A() : x(0), y(0) {} protected: int x; int y; }; class B : public A { public: B() : A(), z(0) {} B(const A& item) : A(), z(1) { x = item.y;} private: int z; }; The problem is with x = item.y; The access is specified as protected. Why doesn't the constructor of class B have access to A::y?

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  • background colour in opengl

    - by lego69
    I want to change background color of the window after pressing the button, but my program doesn't work, can somebody tell me why, thanks in advance int main(int argc, char* argv[]) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(800, 600); glutInitWindowPosition(300,50); glutCreateWindow("GLRect"); glClearColor(1.0f, 0.0f, 0.0f, 1.0f); <--- glutDisplayFunc(RenderScene); glutReshapeFunc(ChangeSize); glutMainLoop(); system("pause"); glClearColor(0.0f, 1.0f, 0.0f, 1.0f); <--- return 0; }

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  • Ignoring focusLost(), SWT.Verify, or other SWT listeners in Java code.

    - by Zoot
    Outside of the actual SWT listener, is there any way to ignore a listener via code? For example, I have a java program that implements SWT Text Widgets, and the widgets have: SWT.Verify listeners to filter out unwanted text input. ModifyListeners to wait for the correct number of valid input characters and automatically set focus (using setFocus())to the next valid field, skipping the other text widgets in the tab order. focusLost(FocusEvent) FocusListeners that wait for the loss of focus from the text widget to perform additional input verification and execute an SQL query based on the user input. The issue I run into is clearing the text widgets. One of the widgets has the format "####-##" (Four Numbers, a hyphen, then two numbers) and I have implemented this listener, which is a modified version of SWT Snippet Snippet179. The initial text for this text widget is " - " to provide visual feedback to the user as to the expected format. Only numbers are acceptable input, and the program automatically skips past the hyphen at the appropriate point. /* * This listener was adapted from the "verify input in a template (YYYY/MM/DD)" SWT Code * Snippet (also known as Snippet179), from the Snippets page of the SWT Project. * SWT Code Snippets can be found at: * http://www.eclipse.org/swt/snippets/ */ textBox.addListener(SWT.Verify, new Listener() { boolean ignore; public void handleEvent(Event e) { if (ignore) return; e.doit = false; StringBuffer buffer = new StringBuffer(e.text); char[] chars = new char[buffer.length()]; buffer.getChars(0, chars.length, chars, 0); if (e.character == '\b') { for (int i = e.start; i < e.end; i++) { switch (i) { case 0: /* [x]xxx-xx */ case 1: /* x[x]xx-xx */ case 2: /* xx[x]x-xx */ case 3: /* xxx[x]-xx */ case 5: /* xxxx-[x]x */ case 6: /* xxxx-x[x] */ { buffer.append(' '); break; } case 4: /* xxxx[-]xx */ { buffer.append('-'); break; } default: return; } } textBox.setSelection(e.start, e.start + buffer.length()); ignore = true; textBox.insert(buffer.toString()); ignore = false; textBox.setSelection(e.start, e.start); return; } int start = e.start; if (start > 6) return; int index = 0; for (int i = 0; i < chars.length; i++) { if (start + index == 4) { if (chars[i] == '-') { index++; continue; } buffer.insert(index++, '-'); } if (chars[i] < '0' || '9' < chars[i]) return; index++; } String newText = buffer.toString(); int length = newText.length(); textBox.setSelection(e.start, e.start + length); ignore = true; textBox.insert(newText); ignore = false; /* * After a valid key press, verifying if the input is completed * and passing the cursor to the next text box. */ if (7 == textBox.getCaretPosition()) { /* * Attempting to change the text after receiving a known valid input that has no results (0000-00). */ if ("0000-00".equals(textBox.getText())) { // "0000-00" is the special "Erase Me" code for these text boxes. ignore = true; textBox.setText(" - "); ignore = false; } // Changing focus to a different textBox by using "setFocus()" method. differentTextBox.setFocus(); } } } ); As you can see, the only method I've figured out to clear this text widget from a different point in the code is by assigning "0000-00" textBox.setText("000000") and checking for that input in the listener. When that input is received, the listener changes the text back to " - " (four spaces, a hyphen, then two spaces). There is also a focusLost Listener that parses this text widget for spaces, then in order to avoid unnecessary SQL queries, it clears/resets all fields if the input is invalid (i.e contains spaces). // Adding focus listener to textBox to wait for loss of focus to perform SQL statement. textBox.addFocusListener(new FocusAdapter() { @Override public void focusLost(FocusEvent evt) { // Get the contents of otherTextBox and textBox. (otherTextBox must be <= textBox) String boxFour = otherTextBox.getText(); String boxFive = textBox.getText(); // If either text box has spaces in it, don't perform the search. if (boxFour.contains(" ") || boxFive.contains(" ")) { // Don't perform SQL statements. Debug statement. System.out.println("Tray Position input contains spaces. Ignoring."); //Make all previous results invisible, if any. labels.setVisible(false); differentTextBox.setText(""); labelResults.setVisible(false); } else { //... Perform SQL statement ... } } } ); OK. Often, I use SWT MessageBox widgets in this code to communicate to the user, or wish to change the text widgets back to an empty state after verifying the input. The problem is that messageboxes seem to create a focusLost event, and using the .setText(string) method is subject to SWT.Verify listeners that are present on the text widget. Any suggestions as to selectively ignoring these listeners in code, but keeping them present for all other user input? Thank you in advance for your assistance.

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  • return new string vs .ToString()

    - by Leroy Jenkins
    Take the following code: public static string ReverseIt(string myString) { char[] foo = myString.ToCharArray(); Array.Reverse(foo); return new string(foo); } I understand that strings are immutable, but what I dont understand is why a new string needs to be called return new string(foo); instead of return foo.ToString(); I have to assume it has something to do with reassembling the CharArray (but thats just a guess). Whats the difference between the two and how do you know when to return a new string as opposed to returning a System.String that represents the current object?

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  • Python nested function scopes

    - by Thomas O
    I have code like this: def write_postcodes(self): """Write postcodes database. Write data to file pointer. Data is ordered. Initially index pages are written, grouping postcodes by the first three characters, allowing for faster searching.""" status("POSTCODE", "Preparing to sort...", 0, 1) # This function returns the key of x whilst updating the displayed # status of the sort. ctr = 0 def keyfunc(x): ctr += 1 status("POSTCODE", "Sorting postcodes", ctr, len(self.postcodes)) return x sort_res = self.postcodes[:] sort_res.sort(key=keyfunc) But ctr responds with a NameError: Traceback (most recent call last): File "PostcodeWriter.py", line 53, in <module> w.write_postcodes() File "PostcodeWriter.py", line 47, in write_postcodes sort_res.sort(key=keyfunc) File "PostcodeWriter.py", line 43, in keyfunc ctr += 1 UnboundLocalError: local variable 'ctr' referenced before assignment How can I fix this? I thought nester scopes would have allowed me to do this. I've tried with 'global', but it still doesn't work.

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  • VB.NET function that takes other functions as a parameter, and executes them

    - by rob
    Hello, Is there a way in vb.net to create a sub/function that will take as an argument some kind of pointer to another function, and allow this new sub/function to execute the passed function? What I have are 10-12 xml-rpc functions I am calling against a remote server. Each of these functions has different argument lists (one takes 1 string, another might take 3 strings and one int, etc). All of them return an object. As I am calling these, it seems like it should be able to be factored better. For instance, everytime I call any of these functions, I want to test the return value for a session drop, and do something to try and reconnect to the remote system, etc. Using .net 3.5 Thanks! -R

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  • Does C99 guarantee that arrays are contiguous ?

    - by kriss
    Following an hot comment thread in another question, I came to debate of what is and what is not defined in C99 standard about C arrays. Basically when I define a 2D array like int a[5][5], does the standard C99 garantee or not that it will be a contiguous block of ints, can I cast it to (int *)a and be sure I will have a valid 1D array of 25 ints. As I understand the standard the above property is implicit in the sizeof definition and in pointer arithmetic, but others seems to disagree and says casting to (int*) the above structure give an undefined behavior (even if they agree that all existing implementations actually allocate contiguous values). More specifically, if we think an implementation that would instrument arrays to check array boundaries for all dimensions and return some kind of error when accessing 1D array, or does not give correct access to elements above 1st row. Could such implementation be standard compilant ? And in this case what parts of the C99 standard are relevant.

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  • How do you insert 9 MB file into a Blob Field Using Oracle.DataAccess?

    - by discwiz
    Trying to insert a large audio file into an Oracle 10g database and keep getting this error: ORA-01460: unimplemented or unreasonable conversion requested The byte array length of the audio file is 2702577. The procedure works with smaller array lengths, but not the larger ones. Here is my code and Thanks! Dim oracleConnection As New OracleClient.OracleConnection Dim Cmd As New OracleClient.OracleCommand Dim oracleDataAdapter As New OracleDataAdapter oracleConnection.ConnectionString = System.Configuration.ConfigurationManager.AppSettings("MasterConnectionODT") Cmd.Connection = oracleConnection Cmd.CommandText = "Audio.ADD_AUDIO" Cmd.CommandType = CommandType.StoredProcedure Dim aParam As New OracleClient.OracleParameter aParam.ParameterName = "I_FACILITY_ID_C" aParam.OracleType = OracleType.Char aParam.Value = FacID aParam.Direction = ParameterDirection.Input Cmd.Parameters.Add(aParam) aParam = New OracleParameter aParam.ParameterName = "I_TARP_ID_N" aParam.OracleType = OracleType.Number aParam.Value = TarpID aParam.Direction = ParameterDirection.Input Cmd.Parameters.Add(aParam) aParam = New OracleParameter aParam.ParameterName = "I_AUDIO_BLOB" aParam.OracleType = OracleType.Blob aParam.Value = Audio aParam.Direction = ParameterDirection.Input Cmd.Parameters.Add(aParam) Using oracleConnection oracleConnection.Open() Cmd.ExecuteNonQuery() End Using

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  • error C2065: undeclared identifier

    - by karikari
    Currently, I have this function inside my other cpp file: UINT32 functionHtml(const wchar_t *url) { WinHttpClient client(url); client.SendHttpRequest(); wstring httpResponseHeader = client.GetHttpResponseHeader(); wstring httpResponse = client.GetHttpResponse(); writeToLog(httpResponse.c_str()); return 0; } I have another cpp file, and I would like to execute the stuff inside the above file. Here is the code for the other file: HRESULT CButtonDemoBHO::onDocumentComplete(IDispatch *pDisp, VARIANT *vUrl){ ATLTRACE("CButtonDemoBHO::onDocumentComplete %S\n", vUrl->bstrVal); // <---- i would like to call funtionHTML here or .. if (isMainFrame(pDisp)){ m_normalPageLoad=false; // <---- here.. MessageBox(m_hWnd, L"Main Document has completed loading", L"Document Complete", MB_OK); return S_OK; } return S_OK; } I got the error C2065: 'url' : undeclared identifier. Need help.

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  • [wxWidgets] How to store wxImage into database, using C++?

    - by Thomas Matthews
    I have some wxImages and I would like to store them into a BLOB (Binary Large OBject) field in a MySQL database. There are no methods in wxImage nor wxBitmap for obtaining the binary data as an array of unsigned char so I can load into the database. My current workaround is to write the image to a temporary file, then load the BLOB field directly from the file. Is there a more efficient method to load and store a wxImage object into a MySQL BLOB field? I am using MySql C++ connector 1.05, MS Visual Studio 2008, wxWidgets and C++.

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  • cannot edit any php files using specific functions

    - by user458474
    I cannot update any txt files using php. When I write a simple code like the following: <?php // create file pointer $fp = fopen("C:/Users/jj/bob.txt", 'w') or die('Could not open file, or fike does not exist and failed to create.'); $mytext = '<b>hi. This is my test</b>'; // write text to file fwrite($fp, $mytext) or die('Could not write to file.'); $content = file("C:/Users/jj/bob.txt"); // close file fclose($fp); ?> Both files do exist in the folder. I just cannot see any updates on bob.txt. Is this a permission error in windows? It works fine on my laptop at home. I also cannot change the php files on my website, using filezilla.

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  • explicit copy constructor or implicit parameter by value

    - by R Samuel Klatchko
    I recently read (and unfortunately forgot where), that the best way to write operator= is like this: foo &operator=(foo other) { swap(*this, other); return *this; } instead of this: foo &operator=(const foo &other) { foo copy(other); swap(*this, copy); return *this; } The idea is that if operator= is called with an rvalue, the first version can optimize away construction of a copy. So when called with a rvalue, the first version is faster and when called with an lvalue the two are equivalent. I'm curious as to what other people think about this? Would people avoid the first version because of lack of explicitness? Am I correct that the first version can be better and can never be worse?

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  • Passing big multi-dimensional array to function in C

    - by kirbuchi
    Hi, I'm having trouble passing a big array to a function in C. I declare: int image[height][width][3]={}; where height and width can be as big as 1500. And when I call: foo((void *)image,height,width); which is declared as follows: int *foo(const int *inputImage, int h, int w); I get segmentation fault error. What's strange is that if my values are: height=1200; width=290; theres no problem, but when they're: height=1200; width=291; i get the mentioned error. At 4 bytes per integer with both height and width of 1500 (absolute worst case) the array size would be of 27MB which imo isn't that big and shouldn't really matter because I'm only passing a pointer to the first element of the array. Any advice?

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  • Accessing WPF Template for Custom Control from Code behind

    - by Ashwani Mehlem
    Hi, i am trying to access a named grid inside a default template for a custom control from code behind. But it seems that the template for the control is null, even after calling ApplyTemplate(). Is that impossible inside the controls constuctor? Here's the code: Generic.xaml: ... <ControlTemplate TargetType="{x:Type local:TimeTableControl}"> <Grid Name="ContentGrid"> </Grid> </ControlTemplate> ... TimeTableControl.cs: public TimeTableControl() { ApplyTemplate(); contentGrid = (Grid)(Template.FindName("ContentGrid", this)); //Line above causes null-pointer-exception ... }

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  • Unix Piping using Fork and Dup

    - by Jacob
    Lets say within my program I want to execute two child processes, one to to execute a "ls -al" command and then pipe that into "wc" command and display the output on the terminal. How can I do this using pipe file descriptors so far the code I have written: An example would be greatly helpful int main(int argc, char *argv[]) { int pipefd[2] pipe(pipefd2); if ((fork()) == 0) { dup2(pipefd2[1],STDOUT_FILENO); close(pipefd2[0]); close(pipefd2[1]); execl("ls", "ls","-al", NULL); exit(EXIT_FAILURE); } if ((fork()) == 0){ dup2(pipefd2[0],STDIN_FILENO); close(pipefd2[0]); close(pipefd2[1]); execl("/usr/bin/wc","wc",NULL); exit(EXIT_FAILURE); } close(pipefd[0]); close(pipefd[1]); close(pipefd2[0]); close(pipefd2[1]); }

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  • Qt drag & drop button; drop not detecting

    - by Thomas Verbeke
    I'm creating a 2D game in QT and i'm trying to implement a drag & drop into my program. For some reason the drop is not registered: qDebug should print a message on dropping but this doesn't happen. #include "dialog.h" #include "ui_dialog.h" #include "world.h" #include <vector> Dialog::Dialog(QWidget *parent) : QDialog(parent), ui(new Ui::Dialog) { ui->setupUi(this); scene = new QGraphicsScene(this); ui->graphicsView->setScene(scene); MySquare *item; QGraphicsRectItem *enemyItem; World *myWorld = new World(); std::vector<Tile*> tiles = myWorld->createWorld(":/texture.jpg"); int count = 0; foreach (Tile *tile, tiles){ count++; item = new MySquare(tile->getXPos()*4,tile->getYPos()*4,4,4); item->setBrush(QColor(tile->getValue()*255,tile->getValue()*255,tile->getValue()*255)); item->setAcceptDrops(true); scene->addItem(item); } player = new MySquare(10,20,10,10); player->setAcceptDrops(true); scene->addItem(player); //drag & drop part QPushButton *pushButton = new QPushButton("Click Me",this); connect(pushButton,SIGNAL(pressed()),this,SLOT(makeDrag())); setAcceptDrops(true); } void Dialog::makeDrag() { QDrag *dr = new QDrag(this); // The data to be transferred by the drag and drop operation is contained in a QMimeData object QMimeData *data = new QMimeData; data->setText("This is a test"); // Assign ownership of the QMimeData object to the QDrag object. dr->setMimeData(data); // Start the drag and drop operation dr->start(); } mysquare.cpp #include "mysquare.h" MySquare::MySquare(int _x,int _y, int _w, int _h) { isPlayer=false; Pressed=false; setFlag(ItemIsMovable); setFlag(ItemIsFocusable); setAcceptDrops(true); color=Qt::red; color_pressed = Qt::green; x = _x; y = _y; w = _w; h = _h; } QRectF MySquare::boundingRect() const { return QRectF(x,y,w,h); } void MySquare::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) { QRectF rec = boundingRect(); QBrush brush(color); if (Pressed){ brush.setColor(color); } else { brush.setColor(color_pressed); } painter->fillRect(rec,brush); painter->drawRect(rec); } void MySquare::mousePressEvent(QGraphicsSceneMouseEvent *event) { Pressed=true; update(); QGraphicsItem::mousePressEvent(event); qDebug() << "mouse Pressed"; } void MySquare::mouseReleaseEvent(QGraphicsSceneMouseEvent *event) { Pressed=false; update(); QGraphicsItem::mousePressEvent(event); qDebug() << "mouse Released"; } void MySquare::keyPressEvent(QKeyEvent *event){ int x = pos().x(); int y = pos().y(); //key handling QGraphicsItem::keyPressEvent(event); } void MySquare::dropEvent(QDropEvent *event) { qDebug("dropEvent - square"); // Unpack dropped data and handle it the way you want qDebug("Contents: %s", event->mimeData()->text().toLatin1().data()); } void MySquare::dragMoveEvent(QDragMoveEvent *event){ qDebug("dragMoveEvent - square "); event->accept(); } void MySquare::dragEnterEvent(QDragEnterEvent *event){ event->setAccepted(true); qDebug("dragEnterEvent - square"); event->acceptProposedAction(); } void MySquare::setBrush(QColor _color){ color = _color; color_pressed = _color; update(); //repaint } edit; there is no problem with qDebug() i'm just using it to test them i'm inside the drag events..which i'm not

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  • How do I use texture-mapping in a simple ray tracer?

    - by fastrack20
    I am attempting to add features to a ray tracer in C++. Namely, I am trying to add texture mapping to the spheres. For simplicity, I am using an array to store the texture data. I obtained the texture data by using a hex editor and copying the correct byte values into an array in my code. This was just for my testing purposes. When the values of this array correspond to an image that is simply red, it appears to work close to what is expected except there is no shading. The bottom right of the image shows what a correct sphere should look like. This sphere's colour using one set colour, not a texture map. Another problem is that when the texture map is of something other than just one colour pixels, it turns white. My test image is a picture of water, and when it maps, it shows only one ring of bluish pixels surrounding the white colour. When this is done, it simply appears as this: Here are a few code snippets: Color getColor(const Object *object,const Ray *ray, float *t) { if (object->materialType == TEXTDIF || object->materialType == TEXTMATTE) { float distance = *t; Point pnt = ray->origin + ray->direction * distance; Point oc = object->center; Vector ve = Point(oc.x,oc.y,oc.z+1) - oc; Normalize(&ve); Vector vn = Point(oc.x,oc.y+1,oc.z) - oc; Normalize(&vn); Vector vp = pnt - oc; Normalize(&vp); double phi = acos(-vn.dot(vp)); float v = phi / M_PI; float u; float num1 = (float)acos(vp.dot(ve)); float num = (num1 /(float) sin(phi)); float theta = num /(float) (2 * M_PI); if (theta < 0 || theta == NAN) {theta = 0;} if (vn.cross(ve).dot(vp) > 0) { u = theta; } else { u = 1 - theta; } int x = (u * IMAGE_WIDTH) -1; int y = (v * IMAGE_WIDTH) -1; int p = (y * IMAGE_WIDTH + x)*3; return Color(TEXT_DATA[p+2],TEXT_DATA[p+1],TEXT_DATA[p]); } else { return object->color; } }; I call the colour code here in Trace: if (object->materialType == MATTE) return getColor(object, ray, &t); Ray shadowRay; int isInShadow = 0; shadowRay.origin.x = pHit.x + nHit.x * bias; shadowRay.origin.y = pHit.y + nHit.y * bias; shadowRay.origin.z = pHit.z + nHit.z * bias; shadowRay.direction = light->object->center - pHit; float len = shadowRay.direction.length(); Normalize(&shadowRay.direction); float LdotN = shadowRay.direction.dot(nHit); if (LdotN < 0) return 0; Color lightColor = light->object->color; for (int k = 0; k < numObjects; k++) { if (Intersect(objects[k], &shadowRay, &t) && !objects[k]->isLight) { if (objects[k]->materialType == GLASS) lightColor *= getColor(objects[k], &shadowRay, &t); // attenuate light color by glass color else isInShadow = 1; break; } } lightColor *= 1.f/(len*len); return (isInShadow) ? 0 : getColor(object, &shadowRay, &t) * lightColor * LdotN; } I left out the rest of the code as to not bog down the post, but it can be seen here. Any help is greatly appreciated. The only portion not included in the code, is where I define the texture data, which as I said, is simply taken straight from a bitmap file of the above image. Thanks.

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