I want to do a basic thing but for some strange reason there is something not working.
I need to write to a file but I'm handling all the code in a callback function, which in turn is declared in a class. Here is the architecture of my code:
Code:
int main (int argc, char **argv) {
ImageConverter Aclass;
while(1); //infinite loop
return 0;
[Code] ....
But this doesn't work, the file gets created but it allways overwrites itself which is not what I need to do.
What I am doing wrong? Is it because i am constantly declaring outfile?
I have a problem with an extension DLL that has an exported function. The function is being exported ok, it is called by a Windows service. The Windows service is using the exported function, and everything works. I am trying to create a file with:
But nothing happnes however. There are no errors, the file is just not created. Also, if i try to call MessageBox() in the exported function, nothing happens as well . I have a .h file which exports the function with __declspec(dllexport) DWORD WINAPI functionName(), and also a .cpp file with the function definition. There is no main().
There is already a thread with exactly the same problem I have, but the answer to solve the problem isn't stated at the end. Problem with callback as classmember.
I have a function (name Callback), with take some parameter( name Arg). I want to create it before, pass it to other class ( class B). And in class B, call the Callback function with Arg paramater. It's something like this:
class A { void A::doSomething(int a, bool b){//dosomething}; void A::setCallback(B b) {//I don't know how to do this};
[Code].....
How can i do this? And what happen with I want B can get more type of callback function, which mean I don't know the type of Callback's paramater?
Is it possible to read NFC card reader in VC++/MFC. Is it possible to develop a callback function that will read the NFC device, and see once the card is inserted, it takes that value from the card and store it in a DB?
I have made a calendar that looks similar to Outlook, and I have the next/previous buttons, but they don't do anything when you click them. how to create the callback so that when I click next it goes to the next month?
If I do a pthread_join in fopen_t() it works perfectly fine. But if I do that in main() I get a segmentation fault error. I want to call it in main() because I want it to be non-blocking, is there any solution?
I have an application based around a WCF Duplex service. I have problems when the user "Restarts" the work the application does... under the hood, the client side closes the connection to the WCF service and creates another. The Service contract is defined like so...
[ServiceContract(Namespace="net.tcp://namespace.MyService", SessionMode=SessionMode.Required, CallbackContract=typeof(IServiceCallback))] public interface IMyService { [OperationContract(IsOneWay=true)]
[Code] ....
The issue I see is that the _context.Close() call always times out and throws an exception. Although I'm then aborting the channel, this feels wrong to me, and I believe it's the cause of freezing in my application. Why the Close() call fails?
I missed something earlier regarding my callback implementation that might be relevant. It looks something like this:
[Callbackbehavior(ConcurrencyMode = ConcurrencyMode.Single, UseSynchronizationContext = false, IncludeExceptionDetailInFaults = true)] public class CallbackImplementation : IServiceCallback { public void SendMessage(string message){ // Do something with the message } }
The exception message is "The ServiceHost close operation timed out after 00:00:30. This could be because a client failed to close a sessionful channel within the required time. The time allotted to this operation may have been a portion of a longer timeout.". There's no inner exception.
The big problem is that the client application freezes when the main application process is started after one client has been disposed and a new one created. I've also noticed that when you close the WPF application, it doesn't close properly and keeps running in the background, preveting you from starting a new instance.
I am writing a simple file/text parser to read a config file for some code I am working on. It's dead simple and not particularly smart but it should get the job done. The code reads a config file:
Here is where it gets wierd. You'll notice that there is an unused variable (filepath) in the config struct. This variable is not referenced or used anywhere in the code, ever. Yet if I comment out the declaration of char filepath[1024], the code segfaults partway through the read_config() function.
My best guess is that there is a buffer overflow elsewhere and it just so happens that the memory allocated for filepath happened to be there to catch it up until now, but I can't work out where it might be happening. With the declaration commented out, the read_config() function gets as far as reading the "padding" variable before it crashes. Yet when the declaration is there, then all the variabled are read correctly and everything seems to work.
One of my class assignments is to create a program that receive a .txt file containing a students name and their grades as follows: John K. 99, 87, 57, 89, 90, 95 Amanda B. Jones 100, 88, 76, 99, 86, 92 etc.. The number of students is unknown until run time. You have to take those grades and average them weighing the first (4) at 10% a piece and the next (2) at 15% each and the final at 30%. Then return an output file with the students name and their letter grade A,B,C,D,F based on their computed score. In addition, on screen it needs to display the average scores for each Q1, Q2, etc. as well as the minimum and maximum for each test on the screen. I am having a hard time in assigning the scores to a variable so that they can then be computed as an average and then used to determine a letter grade. I have begun to write the code and am a bit stuck..here's what I have so far:
Code: // // main.c // Final Exam //
[Code].....
The problem I'm having now is how to go about passing the grades to the function computeGrade and then compute the average and return that to the function.
I'm writing a function that compares two fraction. if the fractions are equal it returns 0. If the fraction in the first parameter is less than the fraction in the second parameter it returns a negative number. Otherwise it returns a positive number. in doing so convert the fraction to a floating point number.
completing the function to run
typedef struct fracion { int numo; int denom; }fraction;
I'm writing a program using Huffman algorithm to compress text file. I have tested my program by just printing the printing ASCII character to file and it worked fine. However, now I have to implement using bits and my program doesn't work. It seems like I'm not reading or writing the right bits. Here is the result of my testing:In the input file I put abc the input file to compress it. Then I uncompress it the out out is aaa. Below is a snippet of how I read and write bits
Code: class BitInput { istream& in; // the istream to delegate to char buf; // the buffer of bits int nbits; public:
I have a question about an issue I am having on my final project. Within my ItemEntry.cs form, I am trying to get the application to append the already existing .txt file, rather than prompt the user to replace it. I can't seem to get the StreamWriter and FileStream to allow the user to write to the file.
Code: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq;
I am trying to write a structure to a file. Example say the structure has two variables x and y . I want to write a function which modifies these variables and stores the modified version on a file. Such that next time I call the function . it has the values from the previous write. Here's an example of my code .
// do some calculations. fwrite(mystruct, sizeof(MYSTRUCT), 1, fp); fclose(fp)
//return some value }
The problem is that each time I run the program it shows the initialized value of the variables and not the value from last write. I guess the write isn't successful because when I open in w+ mode. i get the error file could not be opened and then i have to delete the file and re create it....
I have a text file containing 500 signed decimal numbers. My task is to read each entry and convert into a 16-bit 2's complement representation (binary number) and write into the another text file.
Is there a way to read and write to the same file?
I'm writing a game program and I want to save the score at the end of the game to a txt file. The txt file already contains other game scores. How do I store the score without overwriting the previous scores.
I want to write a program in cpp which will create a file and write some classes into it so that whenever i will execute that program i will have the auto generated file. How to do it....
