C++ :: Making Programs To Work With Custom Hardware / Drivers?
Dec 1, 2014
Recently I got a drawing tablet. One valued feature of this tablet is that it is pressure sensitive (2048 levels). No matter what the model, almost every company's tablet's features (like pressure) are compatible with well-known commercial products like Photoshop, and this is precisely what I'm wondering about:
If well-known graphic products can do it, how do I make my own program to recognize this device's features? How can I access/extract real-time data from a device. Assuming I have all driver stuff correctly installed.
I've been trying to google keywords like "[company] header files" or "[company] developing programs" or stuff like that to no avail... not really sure what to search for.
If you need specific information about the actual device, I will post it, but I'm also just looking for general knowledge about how to this type of thing, with any device.
(I'm not talking about a GUI or how to actually code graphics to respond to the pressure, just about receiving information from it.)
I am starting a project in a few weeks that needs to be able to prevent an executable from running until it has been checked for various criteria (think of it as a DIY anti virus).
My main idea is to build a file filter driver in C to hook into file system reads and writes and prevent executables that I don't like from executing off the disk.
How to get this code to compile and build. It gives me a really strange error saying:
"1>Project 7 Code.obj : error LNK2019: unresolved external symbol "void __cdecl checkAnswers(char * const,char * const,int,int)" (?checkAnswers@@YAXQAD0HH@Z) referenced in function _main 1>C:UsersHaruha Raharu HarukoDesktopSpring 2015 Class WorkIntro to ProgrammingProject 7Project 7DebugProject 7.exe : fatal error LNK1120: 1 unresolved externals"
Here is the specifics on the assignment:
"Complete Programming Challenge #12 (Driver's License Exam) with file modification
The State Department of Motor Vehicles (DMV) has asked you to write a program that grades the written portion of the driver's license exam, which has 20 multiple choice questions.
Here are the correct answers:
1. B 5. C 9. C 13. D 17. C 2. D 6. A 10. D 14. A 18. B 3. A 7. B 11. B 15. D 19. D 4. A 8. A 12. C 16. C 20. A
Create a TestGrader class. The class will have an answers array of 20 characters, which holds the correct test answers. It will also have a student array of 20 characters to hold the student's answers. It will have three public member functions that enable user programs to interact with the class: setKey, setStudent, and grade. The setkey function receives a 20-character string holding the correct answers and copies this information into the answers array. The setStudent function will read in the student's answers from the file student.txt and will store the answers in a 20-character array named student. The grade method will compare each student answer to the correct answer in the key.
An applicant must correctly answer 15 or more of the 20 questions to pass the exam. After grading the exam, the program should display the following items:
-the number of right answers and the number of wrong answers -a list of the question numbers for all incorrectly answered questions -a message indicating whether the applicant passed or failed the exam"
I've copied and pasted my code. The main program, the calculateTaxes.cpp function code and my makefile. I am using the makefile to link these two codes together but I get an error when I type 'make' in the command line.
I receive the error code: assign2c.cpp.text+0x169): undefined reference to 'calculateTaxes(float, float, float*, float*, float*)' collect: ld returned 1 exit status make: *** [main.exe] error 1
so here is a basic program i wrote i am thinking of writing a currency conversion program that does multiple conversions and i was thinking it is possible to do something like this couldnt i call them after i write them as functions
usdtoeuro() usdtokuna()
how would i go about doing that? or can you point me to anything?
I have a mobile application for android coded in javascript and a windows form coded in c#. I want my mobile app to send some data to the c# program. It is fine if the transmission is not secure. I searched the net. I found a site called pastebin.com. Unfortunately it provides api for posting and reading data. However I want something, where I can store,read as well as EDIT the data.
I am trying to experiment with programs and databases. Right now I am trying to set up a database so that my program, which currently just appends its results onto a text file, will instead store each result into a database, because this will make things much easier to access than trying to read specific results from an ever-larger, disorganized text file.
I am just starting out learning C and I am using MinGW, Widnows 7, and cmd.exe.I am starting from scratch and learning very short and simple programs, like 20 lines long.After I use MinGW (gcc) to compile, the programs start up rather slowly, sometimes up to about 3-5 seconds. One with a big nested loop even took about 15 seconds to load. After they run once, the next time they run, it's instant.
Last time I learned from this book, I don't remember them starting so slowly. I use the command "gcc sample.c -o sample".It just concerns me that these tiny little programs are starting up so slowly. I'm scared it's a problem with my computer or MinGW installation. When I start making more advanced programs, I don't want them running slower than they ought to be.
I find type casting to be very hard to grasp, I am not sure why. I understand how it works I suppose, but I find it hard to grasp why it would be needed in programming. So my question is, how often is type casting used in general programs? Is there an easier way I could be trying to teach myself about it? I am just using the tutorials provided by this site.
This is a problem I have been having with every program I write since I started using SDL 2. Whenever I compile my code and run my program, everything works perfectly fine until at some point (usually after 3-8 minutes of running), the program will stop responding completely and I will have to exit out of the console to close it. The code I believe is relevant is:
void MainLoop() { InitLoop(); while ( !QuitMain )
[Code].....
If I change SDL_PollEvent(&Event) to SDL_WaitEventTimeout(&Event,100), then the problem goes away (I did that and had the program running for about an hour without it stop responding before I decided that it solved the problem), so I believe that the problem has something to do with event handling. Also, it might be noteworthy to mention that when I use SDL_WaitEventTimeout with the second parameter being a small number (because 100 milliseconds is a long time to wait and makes the program run at like 8 FPS), the problem returns.
I have learned the basics you need to know about c++ so I was wondering, how do you make a GUI from scratch without using any programs like qt, daniweb, ect. Is there like a ongui() or something?
Is there any way to find the variables declared or defined in a c program and print those variables?? E.g. this is the code
#include<stdio.h> int main() { int a, b, c; printf("Enter two numbers to add"); scanf("%d%d",&a,&B)/>; c = a + b; printf("Sum of entered numbers = %d",c); return 0; }
I want to print all the variables been used. I used (gdb) info locals but its not giving the proper ouput.
I am using a windows application to start other processes. I am looking for a way to keep the form itself as the topmost program until it is closed, allowing the other programs enough load time.
I'm trying to set up some basic communication between two programs via the registry.
For this I would like to use the functions
Code: int value=10; CString strSection="Data"; CWinApp* pApp = AfxGetApp(); pApp->WriteProfileInt(strSection,ValueName,value); and
Code: CString strSection="Data"; CWinApp* pApp = AfxGetApp(); int value=pApp->GetProfileInt(strSection,ValueName,0); which read/write to the application's registry.
Is there some way of making two different programs use the same application registry?
have the 2nd program grab the stored variables to reform some number crunching, without interfering with the UI program, and once done, have it drop the answers back into that DLL, so that the UI can grab it when it's ready.
I have made the 2 programs, + dll
What I've Achieved:
the first program accesses the dll, and loads up a variable (and stays connected to the dll, so that the Dll instance doesn't reset)
I've gotten the DLL to output the variable to make sure it's received it, and stored it to it's own global variable.
the second program connects to the dll successfully, but when it tries to retrieve the data, it returns 0's (NULL's)
My research:from what I've read, so long the dll is connected to a program, all additional programs will attach to the same instance.
how do I make the global variable in the dll be accessible to both programs? (without resorting to saving it to the HDD Idealy)
I am currently trying to write a test program involving constructors. I know what I am about to ask is pretty basic stuff but Visual Studio is not recognizing when I declare strings for some reason. My code isn't completed yet but as I am typing string in to declare the variable in the class Visual Studio is not recognizing string as a usable value.
i saved it with name PIYUSHAN.cpp.after compiling above program, it shows no errors, that means it get compiled successfully. but when I try to run this program it shows Linker error :
Undefined symbol add(int,int) in module PIYUSHAN.CPP Linker error : Undefined symbol sub(int,int) in module PIYUSHAN.CPP Linker error : Undefined symbol mul(int,int) in module PIYUSHAN.CPP Linker error : Undefined symbol div(int,int) in module PIYUSHAN.CPP
I'm building a simple little program for minecraft to reduce the repetitiveness, I'm using getpixel, it's slow, but i only need to grab about 6-12 pixels.
but the problem is, I can get the pixel data if I capture from the entire desktop display, but as soon as I tell it to grab from the active window (wich goes MUCH faster) it doesn't return any colour value's.
I'd rather not have to use getDIBits or program in java or anything since I want to keep it fairly kiss, and if it can't be done, then.. ah well, I'll just grab from the entire desktop, speed isn't to much of an issue, but it'll be a pain to keep the window at the same place.
Code: #include <Windows.h> #include <iostream> using namespace std; // vvv Ignore this, it's just used for retrieving the handle of a window without giving the full window name vvvv struct results {
So lately I've been writing multiple header and cpp files and I would always the same error when I finally #include headers in my main.cpp. This error
Code: undefined reference to `...`
On Youtube videos I see people doing this and their work magically compiles correctly. I found out that when I #include the headers' cpp files instead, my programs would compile. I use Code::Blocks with GNU GCC compiler.
I have started using code::blocks for practicing ,(was using bloodshed dev C++ til now). The thing is that m not able to compile multiple programs stored under a single project , as i have created project by the name of a topic and have decided to solve all problems related to that topic under that project.
When there was only one .cpp file in the project it compiled successfully ,but as soon as i created a second file and compiled it it says "main can be declared only once"
In my program I am supposed to call isEqualTo with a user defined class type, and print out if my two numbers being compared are equal or not. I had to write two versions of this, one with just a template which works fine, but when I implemented the class, all the sudden my program just spews out true no matter if actually equal or not. Here is what I have so far:
#include "stdafx.h" #include <iostream> #include "UserClass.h" using namespace std;
template<typename T> bool isEqualTo(T value1, T value2){ if (value1 == value2)
