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  • staying within boundaries of image?

    - by codefail
    So I am to loop through copyFrom.pixelData and copy it into pixelData. I realize that I need to check the conditions of i and j, and have them not copy past the boundaries of pixelData[x][y], I need another 2 loops for that? I tried this, but was getting segmentation fault.. Is this the right approach? void Image::insert(int xoff, int yoff, const Image& copyFrom, Color notCopy) { for (int x = xoff; x < xoff+copyFrom.width; x++) { for (int y = yoff; y < yoff+copyFrom.height; y++) { for (int i = 0; i<width; i++){ for (int j = 0; j<height; j++){ if (copyFrom.pixelData[i][j].colorDistance(notCopy)>20 ) pixelData[x][y]=copyFrom.pixelData[i][j]; } } } } }

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  • Creating anonymous functions in loop with not the same arguments

    - by onio9
    Hello! I want to make in loop set of buttons, and add to them some events, but anonymous functions is the same. I write example code: for(var i:int=0;i<5;i++) { var button:SimpleButton = new SimpleButton(...); ... button.addEventListener(MouseEvent.CLICK, function(event:MouseEvent):void { trace(i); }); } ... And I want to trace 1,2,3.. from click buttons instead of 4,4,4,4 .. Do you know how can I make this ?

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  • Copy Paste is Disabled in Property Grid

    - by ofarooq
    Hi All, I have a FileNameEditor inside a property grid, which has a few entries like Main File : "C:\blah1" Sec File: "C:\blah2" and so on. My problem is that I cannot copy and paste from one property entry to another, and I cannot type in the fields manually as well. Is there a specific property that will enable editing inside the FileNameEditor. Example public class MyEditor : FileNameEditor { public override bool GetPaintValueSupported(ITypeDescriptorContext context) { return false; } public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value) { object e = base.EditValue(context, provider, value); if ((value as MyFileS) != null) { (value as MyFilesS).FileName = (String) e; } return e; } protected override void InitializeDialog(OpenFileDialog openFileDialog) { base.InitializeDialog(openFileDialog); } } Thanks

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  • How can i do re coding without assign null value?

    - by Phsika
    How can i do below without assign null value "Tex=null"? static void Main(string[] args) { FileInfo f = new FileInfo("C:/temp/Arungg.txt"); StreamWriter Tex; Tex = null; if (!f.Exists) { f.CreateText(); } else { Tex = f.AppendText(); } Tex.WriteLine("Test1"); Tex.WriteLine("Test2"); Tex.Write(Tex.NewLine); Tex.Close(); Console.WriteLine(" The Text file named Arungg is created "); }

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  • Getting a Type variable knowing the name of type C#

    - by StuffHappens
    Hello! I'm developing a TypeTranslator class which has a method Type TranslateType(Type type). This method gets a type of an interface and if there's a class of interface name without leading I it creates it, otherwise an exception is raised. Here's some code to clearify what's written before: class Program { interface IAnimal { } class Animal : IAnimal { } void Function() { TypeTranslator typeTranslator = new TypeTranslator(); Assert(typeTranslator.TranslateType(typeof(IAnimal) == typeof(Animal))); } } Is it possible to get what I want? Thank you for your help!

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  • Why Is It That Generics Constraint Can't Be Casted to Its Derived Type?

    - by Ngu Soon Hui
    It is quite puzzling to find out that Generics Constraint Can't Be Casted to Its Derived Type. Let's say I have the following code: public abstract class BaseClass { public int Version { get { return 1; } } public string FixString { get; set; } public BaseClass() { FixString = "hello"; } public virtual int GetBaseVersion() { return Version; } } public class DeriveClass: BaseClass { public new int Version { get { return 2; } } } And guess what, this method will return a compilation error: public void FreeConversion<T>(T baseClass) { var derivedMe = (DeriveClass)baseClass; } I would have to cast the baseClass to object first before I can cast it to DerivedClass. Seems to me pretty ugly. Why this is so?

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  • DrawImage in XP Mode or Remote Desktop

    - by simplecoder
    I'm displaying a PNG with a transparent background that looks good in Windows 7, but then I run my app in XP Mode or remote desktop to a Windows XP machine and the PNG looks incorrect. I noticed that if I disable "Integration Mode" or run the app on XP without remote desktop, the image looks fine. How do I get DrawImage to render the PNG correctly in XP Mode or remote desktop? Image inside Windows 7 Image inside XP Mode or remote desktop Here's my code: protected override void OnPaint(PaintEventArgs e) { Image image = Image.FromFile("hello.png", false); Bitmap bmp = new Bitmap(image); Rectangle destRect = new Rectangle(0, 0, image.Width, image.Height); e.Graphics.DrawImage(image, destRect, 0, 0, image.Width, image.Height, GraphicsUnit.Pixel); base.OnPaint(e); }

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  • ASP.Net Problem with View Control

    - by tking
    I admit, I'm an .NET n00b. Basically what I'm trying to do is I have a page with a text box on it and an image button. On click of the image button I want it to show a view control I have set up. Inside this view control is an image and some text. So this is what I have in my code-behind. protected void btnSubmit_Click(object sender, ImageClickEventArgs e) { string email = txtUnsubscribe.Text; vwSuccess.Visible = true; } Simple right? Well when I click on the button for submit, I get the "Object reference not set to an instance of an object." error message. Where am I going wrong?

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  • Do I really have to call Focus in OnMouseDown of my custom Control?

    - by Thomas
    I'm implementing a custom control that inherits from Control. I want it to be focusable (it's a kind of list box). In the constructor, I do SetStyle(ControlStyles.Selectable, true); I can now use Tab to navigate to the control. However, when the control receives a mouse click, it does not automatically claim focus. I can work around this, of course: protected override void OnMouseDown(MouseEventArgs e) { Focus(); base.OnMouseDown(e); } But this feels like a kludge that should not be necessary. Is this really the way to go? Or is there some way to tell Control to claim focus automatically when it receives a mouse click?

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  • Help me understand the code snippet in c#

    - by Benny
    I am reading this blog: Pipes and filters pattern I am confused by this code snippet: public class Pipeline<T> { private readonly List<IOperation<T>> operations = new List<IOperation<T>>(); public Pipeline<T> Register(IOperation<T> operation) { operations.Add(operation); return this; } public void Execute() { IEnumerable<T> current = new List<T>(); foreach (IOperation<T> operation in operations) { current = operation.Execute(current); } IEnumerator<T> enumerator = current.GetEnumerator(); while (enumerator.MoveNext()); } } what is the purpose of this statement: while (enumerator.MoveNext());? seems this code is a noop.

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  • Iphone remove sub view

    - by Sharanya
    I have a UINavigationController. On the right top i have a button on click of which i have to get a drop down table view. I created another UIViewController Class, with xib and added it as a subView to the current view. It should appear on 1st click and disappear on the 2nd click. This should happen for all click(open view and close view). I wrote this code but dont know where i'm going wrong. someone please help -(void)modalTableView { tableView1 = [[TableViewController alloc] initWithNibName:@"TableViewController" bundle:nil]; for (UIView *subView in self.view.subviews) { if ([subView isKindOfClass:[TableViewController class]]) { [subView removeFromSuperview]; } else { [self.view addSubview:tableView1.view]; } } } What am i missing here? EDIT : TableViewController is the name of my UIViewController Class

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  • C++ HW - defining classes - objects that have objects of other class problem in header file (out of

    - by kitfuntastik
    This is my first time with much of this code. With this instancepool.h file below I get errors saying I can't use vector (line 14) or have instance& as a return type (line 20). It seems it can't use the instance objects despite the fact that I have included them. #ifndef _INSTANCEPOOL_H #define _INSTANCEPOOL_H #include "instance.h" #include <iostream> #include <string> #include <vector> #include <stdlib.h> using namespace std; class InstancePool { private: unsigned instances;//total number of instance objects vector<instance> ipp;//the collection of instance objects, held in a vector public: InstancePool();//Default constructor. Creates an InstancePool object that contains no Instance objects InstancePool(const InstancePool& original);//Copy constructor. After copying, changes to original should not affect the copy that was created. ~InstancePool();//Destructor unsigned getNumberOfInstances() const;//Returns the number of Instance objects the the InstancePool contains. const instance& operator[](unsigned index) const; InstancePool& operator=(const InstancePool& right);//Overloading the assignment operator for InstancePool. friend istream& operator>>(istream& in, InstancePool& ip);//Overloading of the >> operator. friend ostream& operator<<(ostream& out, const InstancePool& ip);//Overloading of the << operator. }; #endif Here is the instance.h : #ifndef _INSTANCE_H #define _INSTANCE_H ///////////////////////////////#include "instancepool.h" #include <iostream> #include <string> #include <stdlib.h> using namespace std; class Instance { private: string filenamee; bool categoryy; unsigned featuress; unsigned* featureIDD; unsigned* frequencyy; string* featuree; public: Instance (unsigned features = 0);//default constructor unsigned getNumberOfFeatures() const; //Returns the number of the keywords that the calling Instance object can store. Instance(const Instance& original);//Copy constructor. After copying, changes to the original should not affect the copy that was created. ~Instance() { delete []featureIDD; delete []frequencyy; delete []featuree;}//Destructor. void setCategory(bool category){categoryy = category;}//Sets the category of the message. Spam messages are represented with true and and legit messages with false.//easy bool getCategory() const;//Returns the category of the message. void setFileName(const string& filename){filenamee = filename;}//Stores the name of the file (i.e. “spam/spamsga1.txt”, like in 1st assignment) in which the message was initially stored.//const string& trick? string getFileName() const;//Returns the name of the file in which the message was initially stored. void setFeature(unsigned i, const string& feature, unsigned featureID,unsigned frequency) {//i for array positions featuree[i] = feature; featureIDD[i] = featureID; frequencyy[i] = frequency; } string getFeature(unsigned i) const;//Returns the keyword which is located in the ith position.//const string unsigned getFeatureID(unsigned i) const;//Returns the code of the keyword which is located in the ith position. unsigned getFrequency(unsigned i) const;//Returns the frequency Instance& operator=(const Instance& right);//Overloading of the assignment operator for Instance. friend ostream& operator<<(ostream& out, const Instance& inst);//Overloading of the << operator for Instance. friend istream& operator>>(istream& in, Instance& inst);//Overloading of the >> operator for Instance. }; #endif Also, if it is helpful here is instance.cpp: // Here we implement the functions of the class apart from the inline ones #include "instance.h" #include <iostream> #include <string> #include <stdlib.h> using namespace std; Instance::Instance(unsigned features) { //Constructor that can be used as the default constructor. featuress = features; if (features == 0) return; featuree = new string[featuress]; // Dynamic memory allocation. featureIDD = new unsigned[featuress]; frequencyy = new unsigned[featuress]; return; } unsigned Instance::getNumberOfFeatures() const {//Returns the number of the keywords that the calling Instance object can store. return featuress;} Instance::Instance(const Instance& original) {//Copy constructor. filenamee = original.filenamee; categoryy = original.categoryy; featuress = original.featuress; featuree = new string[featuress]; for(unsigned i = 0; i < featuress; i++) { featuree[i] = original.featuree[i]; } featureIDD = new unsigned[featuress]; for(unsigned i = 0; i < featuress; i++) { featureIDD[i] = original.featureIDD[i]; } frequencyy = new unsigned[featuress]; for(unsigned i = 0; i < featuress; i++) { frequencyy[i] = original.frequencyy[i];} } bool Instance::getCategory() const { //Returns the category of the message. return categoryy;} string Instance::getFileName() const { //Returns the name of the file in which the message was initially stored. return filenamee;} string Instance::getFeature(unsigned i) const { //Returns the keyword which is located in the ith position.//const string return featuree[i];} unsigned Instance::getFeatureID(unsigned i) const { //Returns the code of the keyword which is located in the ith position. return featureIDD[i];} unsigned Instance::getFrequency(unsigned i) const { //Returns the frequency return frequencyy[i];} Instance& Instance::operator=(const Instance& right) { //Overloading of the assignment operator for Instance. if(this == &right) return *this; delete []featureIDD; delete []frequencyy; delete []featuree; filenamee = right.filenamee; categoryy = right.categoryy; featuress = right.featuress; featureIDD = new unsigned[featuress]; frequencyy = new unsigned[featuress]; featuree = new string[featuress]; for(unsigned i = 0; i < featuress; i++) { featureIDD[i] = right.featureIDD[i]; } for(unsigned i = 0; i < featuress; i++) { frequencyy[i] = right.frequencyy[i]; } for(unsigned i = 0; i < featuress; i++) { featuree[i] = right.featuree[i]; } return *this; } ostream& operator<<(ostream& out, const Instance& inst) {//Overloading of the << operator for Instance. out << endl << "<message file=" << '"' << inst.filenamee << '"' << " category="; if (inst.categoryy == 0) out << '"' << "legit" << '"'; else out << '"' << "spam" << '"'; out << " features=" << '"' << inst.featuress << '"' << ">" <<endl; for (int i = 0; i < inst.featuress; i++) { out << "<feature id=" << '"' << inst.featureIDD[i] << '"' << " freq=" << '"' << inst.frequencyy[i] << '"' << "> " << inst.featuree[i] << " </feature>"<< endl; } out << "</message>" << endl; return out; } istream& operator>>(istream& in, Instance& inst) { //Overloading of the >> operator for Instance. string word; string numbers = ""; string filenamee2 = ""; bool categoryy2 = 0; unsigned featuress2; string featuree2; unsigned featureIDD2; unsigned frequencyy2; unsigned i; unsigned y; while(in >> word) { if (word == "<message") {//if at beginning of message in >> word;//grab filename word for (y=6; word[y]!='"'; y++) {//pull out filename from between quotes filenamee2 += word[y];} in >> word;//grab category word if (word[10] == 's') categoryy2 = 1; in >> word;//grab features word for (y=10; word[y]!='"'; y++) { numbers += word[y];} featuress2 = atoi(numbers.c_str());//convert string of numbers to integer Instance tempp2(featuress2);//make a temporary Instance object to hold values read in tempp2.setFileName(filenamee2);//set temp object to filename read in tempp2.setCategory(categoryy2); for (i=0; i<featuress2; i++) {//loop reading in feature reports for message in >> word >> word >> word;//skip two words numbers = "";//reset numbers string for (int y=4; word[y]!='"'; y++) {//grab feature ID numbers += word[y];} featureIDD2 = atoi(numbers.c_str()); in >> word;// numbers = ""; for (int y=6; word[y]!='"'; y++) {//grab frequency numbers += word[y];} frequencyy2 = atoi(numbers.c_str()); in >> word;//grab actual feature string featuree2 = word; tempp2.setFeature(i, featuree2, featureIDD2, frequencyy2); }//all done reading in and setting features in >> word;//read in last part of message : </message> inst = tempp2;//set inst (reference) to tempp2 (tempp2 will be destroyed at end of function call) return in; } } } and instancepool.cpp: // Here we implement the functions of the class apart from the inline ones #include "instancepool.h" #include "instance.h" #include <iostream> #include <string> #include <vector> #include <stdlib.h> using namespace std; InstancePool::InstancePool()//Default constructor. Creates an InstancePool object that contains no Instance objects { instances = 0; ipp.clear(); } InstancePool::~InstancePool() { ipp.clear();} InstancePool::InstancePool(const InstancePool& original) {//Copy constructor. instances = original.instances; for (int i = 0; i<instances; i++) { ipp.push_back(original.ipp[i]); } } unsigned InstancePool::getNumberOfInstances() const {//Returns the number of Instance objects the the InstancePool contains. return instances;} const Instance& InstancePool::operator[](unsigned index) const {//Overloading of the [] operator for InstancePool. return ipp[index];} InstancePool& InstancePool::operator=(const InstancePool& right) {//Overloading the assignment operator for InstancePool. if(this == &right) return *this; ipp.clear(); instances = right.instances; for(unsigned i = 0; i < instances; i++) { ipp.push_back(right.ipp[i]); } return *this; } istream& operator>>(istream& in, InstancePool& ip) {//Overloading of the >> operator. ip.ipp.clear(); string word; string numbers; int total;//int to hold total number of messages in collection while(in >> word) { if (word == "<messagecollection"){ in >> word;//reads in total number of all messages for (int y=10; word[y]!='"'; y++){ numbers = ""; numbers += word[y]; } total = atoi(numbers.c_str()); for (int x = 0; x<total; x++) {//do loop for each message in collection in >> ip.ipp[x];//use instance friend function and [] operator to fill in values and create Instance objects and read them intot he vector } } } } ostream& operator<<(ostream& out, const InstancePool& ip) {//Overloading of the << operator. out << "<messagecollection messages=" << '"' << '>' << ip.instances << '"'<< endl << endl; for (int z=0; z<ip.instances; z++) { out << ip[z];} out << endl<<"</messagecollection>\n"; } This code is currently not writing to files correctly either at least, I'm sure it has many problems. I hope my posting of so much is not too much, and any help would be very much appreciated. Thanks!

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  • why this signal handler is called infinitely

    - by lz_prgmr
    I am using Mac OS 10.6.5, g++ 4.2.1. And meet problem with following code: #include <iostream> #include <sys/signal.h> using namespace std; void segfault_handler(int signum) { cout << "segfault caught!!!\n"; } int main() { signal(SIGSEGV, segfault_handler); int* p = 0; *p = 100; return 1; } It seems the segfault_handler is called infinitely and keep on print: segfault caught!!! segfault caught!!! segfault caught!!! ... I am new to Mac development, do you have any idea on what happened?

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  • how to implement a callback in runnable to update other swing class

    - by wizztjh
    I have a thread like this public class SMS { class Read implements Runnable { Read(){ Thread th = new Thread(this); th.start(); } @Override public void run() { // TODO Auto-generated method stub while (true){ Variant SMSAPIReturnValue = SMSAPIJava.invoke("ReadSMS"); if (SMSAPIReturnValue.getBoolean()){ String InNumber = SMSAPIJava.getPropertyAsString("MN"); String InMessage = SMSAPIJava.getPropertyAsString("MSG"); } } } } } How do I update the message to another GUI class in the same package(I understand how to put nested class to another package ....). Should I implement a callback function in SMS class? But how? Or should I pass in the Jlabel into the class?

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  • java.lang.OutOfMemoryError: unable to create new native thread for multiple threads

    - by Kaustubh Ranjan Singh
    static class solver implements Runnable { static calculator(problem){ //Some code if(condition) {solver s = new solver(newproblem); new Thread(s).start();} } Public solver(int newproblem) { this.problem = newproblem ; } public void run() { // TODO Auto-generated method stub calculator(promblem); } } i am having a big array maze of 100x100 and i am trying to solve it and i am getting an error java.lang.OutOfMemoryError: unable to create new native thread(after running a code for some times). How can solve this , How can i use ExecutorService i think that will solve the problem or i want something like thisIf Number of generated threads4K then stop the first 100 threads

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  • Casting as Interface? Awesome.

    - by cam
    I was just experimenting around with one of my programs, trying to make it looks prettier and I found something interesting. I have an interface that 4 classes inherit from. I found that if I pass the Class as an object to a method like so: ClassTest classtest = new ClassTest(); DoOperation(classtest); private void DoOperation(object o) { ((InterfaceClass)o).DoThis(); } So I can pass any type of class that inherits from InterfaceClass, and it will preform the proper interface operation? This is the coolest thing I've ever found from OOP (something I've never really studied) I really thought interfaces were created for the sole purpose of organization for developers. Are there more uses for interfaces than this?

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  • Java Interface Reflection Alternatives

    - by Phaedrus
    I am developing an application that makes use of the Java Interface as more than a Java interface, i.e., During runtime, the user should be able to list the available methods within the interface class, which may be anything: private Class<? extends BaseInterface> interfaceClass. At runtime, I would like to enum the available methods, and then based on what the user chooses, invoke some method. My question is: Does the Java "Interface" architecture provide any method for me to peek and invoke methods without using the Reflection API? I wish there were something like this (Maybe there is): private Interface<? extends BaseInterface> interfaceAPI; public void someMethod(){ interfaceAPI.listMethods(); interfaceAPI.getAnnotations(); } Maybe there is some way to use Type Generics to accomplish what I want? Thanks, Phaedrus

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  • Simple Obj-C Memory Management Question

    - by yar
    This is from some sample code from a book // On launch, create a basic window - (void)applicationDidFinishLaunching:(UIApplication *)application { UIWindow *window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:[[HelloController alloc] init]]; [window addSubview:nav.view]; [window makeKeyAndVisible]; } But a release is never called for window nor for nav. Release should be called since alloc was called, right? If #1 is right, then I would need to store a reference to each of these in an instance variable in order to release them in the dealloc? Perhaps I'm wrong all around...

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  • wifi disconnect event

    - by user986474
    when i get disconnect event by this code : public class WifiReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { String ssid="someSsidName"; ConnectivityManager conMan = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE); NetworkInfo netInfo = conMan.getActiveNetworkInfo(); WifiInfo wifiInfo = null; if (netInfo.getType() == ConnectivityManager.TYPE_WIFI) { //android connect to wifi } else{ //do somthing } } } i try to know what the ssid name when android disconnect. i mean when android disconnect from wifi i need to know it (this i can know by my code) but what i missing is the ssid name android just disconnect from. there is a way to do that? (i know i can save the name when android connect to wifi and use this name when disconnect but this not the way i want...) thanks in advance!

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  • help implementing All Nearest Smaller Values algorithm

    - by davit-datuashvili
    http://en.wikipedia.org/wiki/All_nearest_smaller_values this is site of the problem and here is my code but i have some trouble to implement it import java.util.*; public class stack{ public static void main(String[]args){ int x[]=new int[]{ 0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15 }; Stack<Integer> st=new Stack<Integer>(); for (int a:x){ while (!st.empty() && st.pop()>=a){ System.out.println( st.pop()); if (st.empty()){ break; } else{ st.push(a); } } } } } and here is pseudo code from site S = new empty stack data structure for x in the input sequence: while S is nonempty and the top element of S is greater than or equal to x: pop S if S is empty: x has no preceding smaller value else: the nearest smaller value to x is the top element of S push x onto S

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  • Getting a NullReferenceException Error when invoking a Select File Dialog Box

    - by codingguy3000
    Hey everyone This is a real newbie question. I have simple app that selects a picture and display's that picture in a PictureBox. I decided to mess with the Opacity Attribute so I added a timer and created this cool effect where the Main Form's Opacity is increased by 20% every 400 miliseconds. The problem is that now when I click the button that invokes the Select File Dialog Box I'm getting a NullReferenceException error. private void tmrClock_Tick(object sender, EventArgs e) { if (ViewerForm.ActiveForm.Opacity != 1) { ActiveForm.Opacity = ActiveForm.Opacity + .20; } } The error message is pointing to the if statement. What am I doing wrong? Thanks

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  • I have a ConnectException that isn't being caught for some reason

    - by aakbari1024
    I'm working on an Android application that uses sockets. I have a function called initializeStreams() which opens the socket and attempts a connection. This function throws a ConnectException if the connection could not be established. But for some reason, in the code that calls initializeStreams(), which has a catch block for ConnectException, the log prints out its own stack trace for the exception instead of going to the catch block. The catch block is never reached at all, even though the exact exception is being thrown. Here's the code: The try block: try { initializeStreams(); /* drivesList = new ArrayList<String>(); drivesList = enumerateDrives();*/ } catch (ConnectException e) { //Log.i(TAG, "caught connect exception"); /*loadingProgress.dismiss(); retryConnection();*/ } initializeStreams(): public void initializeStreams() throws ConnectException { try { Log.i(TAG, "Attempting to connect"); requestSocket = new Socket(SERVER_ADDR, PORT); /* other code */ } catch (IOException e) { e.printStackTrace(); } I can't figure this out, so any help would be much appreciated. }

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  • Java program runtime error

    - by Sam
    public class BooksTestDrive { public static void main(String[] args) { Books [] myBooks = new Books[3]; int x=0; myBooks[0].title = "The Grapes of Jave"; myBooks[1].title = "The Java Gatsby"; myBooks[2].title = "The Java Cookbook"; myBooks[0].author = "bob"; myBooks[1].author = "sue"; myBooks[2].author = "ian"; while (x < 3) { System.out.print(myBooks[x].title); System.out.print("by"); System.out.println(myBooks[x].author); x = x+1; } } } This code compiles but while runtime, its giving nullpointer exception.

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  • Virtual methods as Comp function to sort

    - by wilsongoncalo.mp
    Hello everyone! I'm new to C++ and i'm trying to use std::sort function to sort a vector of Solutions. The code is something like this (solution list is a *vector): void SolutionSet::sort(Comparator &comparator) { std::sort(solutionsList_->begin(), solutionsList_->end(), &comparator::compare); } The comparator param is a Comparator´s child class instance , and the compare method is virtual at Comparator class and implemented by all Comparator's child classes. And i want to use that function as a comparator function at std:sort(). Is this possible? If it is, can someone tell me how? Because with the previous code, it doesn't work. If i've not made myself clear, please just ask! Thank you guys!

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  • Const Functions and Interfaces in C++

    - by 58gh1z
    I'll use the following (trivial) interface as an example: struct IObject { virtual ~IObject() {} virtual std::string GetName() const = 0; virtual void ChangeState() = 0; }; Logic dictates that GetName should be a const member function while ChangeState shouldn't. All code that I've seen so far doesn't follow this logic, though. That is, GetName in the example above wouldn't be marked as a const member function. Is this laziness/carelessness or is there a legitimate reason for this? What are the major cons of me forcing my clients to implement const member functions when they are logically called for?

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