Visual C++ :: Passing Variant Variable Through LPVOID
Mar 25, 2013
I have create a function which able to return value for variant of variable through a LPVOID parameter function.
Here is my coding.
Code:
void main()
{
CClassA a;
BOOL bAssign=FALSE;
CString str;
[Code].....
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Dec 12, 2012
I am attaching a sample project. Basically what this project does is that I initialize a variable map<CString, bool*> m_mapTest in CView::OnInitialUpdate and then pass the variable to CDocument class. On the other hand, within the function OnSaveDocument defined in CDocument I check m_mapTest. To my surprise, the CString part of m_mapTest is correct but the bool* part of m_mapTest is wrong(I pass an array of bool in CView::OnInitialUpdate).
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Nov 8, 2013
This code is for a program that allows you to play a guessing game or arithmetic game and shows your total score from both as you go along. The program works fine the only problem I'm having is with the score. Is there a way to call the score value from the outside function into main?
Code:
#include <stdio.h>
#include <time.h>
#include <stdlib.h>
//prototype functions
void menu();
[Code] .....
So trying to pass the value of score from the outer function int guessGame() into the score print statement in choice 3 of the main function? Oh and the "17 -turn_count" was just part of the requirements of the assignment.
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Sep 8, 2014
#include<iostream>
using namespace std;
int main(){
int size_col = 12;
int size_row = 12;
char months_array[12][12] =
[Code] ....
I am having problems with passing a block of a char to a variable, so i could print it out.
It gives me an error: value of type *char cannot be assigned to a entity type char.
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Mar 30, 2014
I have program where i have to check to see if file exist, if it does not then it needs to be created. SO I have a read file that works fine, if th efile exist it reads whats in it, if it does it says the file does not exist. Now Im trying to creata function that creates the file if it doesnt exist. so in my read function when the person enters the name of the file to be checked for..I pass that name to a variable called name..Hoping that I could then pass it into my create file function if it does not exist..and use that variable to pass the name they entered into the createfile array..called filename.. but I am having trouble because i get error when i try to pass from a string name to char array.. even when I change the varialbe name to char, or char [256] it will not work.. I try to fing a way to convert th string to a char using the strncopy function but still no dice..here the code i have for the createfile funciton
void CreateNew(ofstream & FileNew)//Create file
{
char filename[256];
string name;
[Code].....
How can i do this without having to ask the person to enter the file name twice..
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Aug 31, 2014
So I have a class object that contains the private member variable spot and the public member function MoveLock. Within MoveLock, is a member variable called numbers that holds the place where a user is on a "lock knob". Now, what I'm trying to accomplish is that whenever the user turns the "knob" in the wrong direction, the position is updated with that current numbers so that the clicks needed to unlock the first state is also updated. But I get these errors:
Error E2096 C:Users...switchtest.cpp 34: Illegal structure operation in function main()
Error E2294 C:Users...switchtest.cpp 39: Structure required on left side of . or .* in function main()
Ultimately, what I have in main() is a piece of what I'm going to implement in a class member function. I'm also thinking about moving the if else statements out of the for and creating a second one for the else portion.
#include <iostream>
#include <windows.h>
#include <iomanip>
using namespace std;
HANDLE inKeys = GetStdHandle(STD_INPUT_HANDLE);
HANDLE screen = GetStdHandle(STD_OUTPUT_HANDLE);
[code]....
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Dec 24, 2013
I have a quick question about passing multiple variable to a func that has (stringstream & text). Here is the code:
void PrintText(stringstream & txt) {
cout << txt.str() << endl;
}
void main() {
[Code] ....
How to make second one work?
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Jun 16, 2013
Any way to create a variable using a variable in the name? So E.g. if you wanted to create an int named nr(x), and x was 1, you would get an int variable named nr1? How would you do this?
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May 6, 2013
I write a small application and using the following API to open the file:
hHandle = CreateFile(lpszFileName, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
Then I pass the hHandle to a DLL exported function, in that function, I will call
DWORD dwFlags = 0;
ASSERT(GetHandleInformation(hFile,&dwFlags) != 0)
to check if the handle is valid. However, the assert fails. And I use GetLastError to get the error code 6, which means invalid handle.
What is the problem with my codes?
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Jul 19, 2013
having problem passing arguments between main and a function.
I would like to pass three values to a function, have it calculate a 2D matrix and return it back to main. I would like it to accept variable matrix size. Here is my code:
#include "stdafx.h"
#include <cstdlib>
#include <stdlib.h>
#include <math.h>
#include <iostream>
#include <fstream>
[code]....
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Oct 14, 2013
I have a function called,
App 1:
void GetImage(CImage * img) {
//Pass &img over socket to another app
}
App 2:
void DisplayImage() {
CImage * pImg = &img;
}
Is it possible to pass a class pointer as memory buffer across the socket? The above code is just an example. My question in general is, whether it's possible to pass any Classes pointer as a memory buffer across sockets.
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Oct 21, 2012
I'm writing an ActiveX control. In one of the functions I'd like the user to be able to pass me a pointer to a buffer that they created which I can then fill with data and return a success/error code. What's the appropriate way to do this? I was thinking about just using an OLE_HANDLE type for the parameter and then casting that to pointer inside the OCX but I'm not sure if that's safe or the right way to do it.
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Apr 8, 2013
I am doing an project in SDI. I have two functions name sendtext(CString str) and displaytext(CString inr) both in different class. I have a pointer name pView to send the string str to function "displaytext". The problem is after some operations i get a text in str and i send that text to display text in the output screen i get the text and wen the second text comes to "displaytext" the former text disappears and the latest string only present. How can i display both the text in the output window on ClistCtrl class.
Code:
Void sendtext(CString str)
{
// do some operations
................
pView->displaytext(str);
}
void displaytext(CString inr) {
CListCtrl &ctlsde = this->GetListCtrl();
ctlsde.InsertColumn(1, _T("First "), LVCFMT_LEFT, 80);
int nItem;
nItem = ctlsde.InsertItem(0, inr);
}
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Jan 29, 2015
I have a DLL developed using pure VC++ (all unmanaged code that doesn't use .NET framework). This DLL will be deployed in different client PCs within a network and will act like an agent.
Now I have establish a communication between this DLL and a WCF web service, that will be deployed in a server PC. The Service will first get a list of PCs either name or IP Address within a network using LDAP (Active Directory) and once, we get the PCs, I have to establish a communication between the web service and the agents that reside in these client PCs,
How can I accomplish this?
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Apr 9, 2014
I'm using the Visual C++ Express 2008 and i need to pass as parameters to a function characters coded in UTF 8. My environment is Windows 7. The editor of the VC++ write in UTF 8 or UTF 16? If it writes in UTF 16 how can i change it?
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Jul 19, 2013
I have a main dialog which has (DDX?) controls for the user. eg a slider, and a combo box.
Previously, an image adjusted by these controls was in the same dialog.
I need to put this image in a New, separate dialog but it still must be controlled by the slider and combo box on the main dialog.
My question is how can I pass the control's variables between the dialogs? I have, say,
Code:
//MainDlg.cpp
DDX_Control(pDX, IDC_ComboBrightness, m_Brightness
I was told that I could do something like:
Code:
//ImageDlg.h
public:
ImageDlg(CWnd* pParent = NULL, CComboBox m_Brightness); // standard constructor
But I get errors including: Missing default parameter for parameter 2
I also need to pass the image array, is that perhaps the same method?
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Mar 16, 2014
my goal:
have 1 program handle the UI
have that program store variables to a DLL
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)
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Jun 15, 2014
//I dont understand this why does "<< "
The value of global now is: " << global << "
";" is equals to nine
#include <iostream>
int subtract (int a, int b);
int global = 5;
int main(void) {
using std::cout;
int a, b;
[Code] ....
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Oct 3, 2013
Just using Find in my source code to look for variables or whatever, works once or twice then just stops - Doesn't find anything even if it's there. If I restart VS it works again, but not for long.
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Nov 22, 2012
I'm fairly new to C++ and have begun working with pointers. I wish to create am array called sigmaf_point that reads data from a text file. I have managed to get that working, but when it comes to using this pointer I come across some problems. The array is created as such:
Code:
double sigma [5];
double *sigmaf_point = sigma;
void read(double *&sigmaf_point)
string s;
ifstream Dfile;
std::stringstream out;
[Code] .....
I then create a coordinate system inside the main file, as the program I am writing is about modelling the movement of atoms, which requires you to know the coordinates:
Code:
int main();
double **coords_fluid = new double*[5000];
for (int i = 0; i < n_atoms_methane; i++) {
coords_fluid[i] = new double[4];
}
Now, the problem arises when I want to calculate a new variable as so:
Code:
for (int i = 0; i <= n_atoms-1; i++) {
sf1=sigmaf_point(coords_fluid[i][3]);
}
I get the error C2064: term does not evaluate to a function taking 1 arguments, and a red line under sigmaf_point that says it must be pointer to function type. I am a bit confused about this.
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Jun 24, 2014
I have one Tab called Tab4 and one main dialog box called CGrabDlg. The values of my variables are not updated when I change them.?
Here my constructor of my Tab :
Code:
CTab4::CTab4(CWnd* pParent /*=NULL*/)
: CDialogEx(CTab4::IDD, pParent )
, iFilter1(_T("F1_350"))
[Code]....
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Apr 1, 2013
Can local variable be passed as the parameter for a new created thread procedure? Here is the example code:
Code:
void CDLG::some_function()
{
CString strFileName="abc.doc";
//local variable, can it be valid for being passed into the following new thread???
//Can strFileName still be accessed from within the stack of thread procedure?
::AfxBeginThread(ProcessContentThread,(LPVOID)&strFileName);
}
[Code]...
There is another method using variable on the heap,
Code:
void CDLG::some_function()
{
CString strFileName="abc.doc";
CString* pstrFN=new CString(strFileName);
::AfxBeginThread(ProcessContentThread,(LPVOID)pstrFN);
}
[Code]...
I test these code, both methods work as expected, but I doubt whether the first method is a good way. OR if only the second method is the correct way to pass a parameter to a thread.
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Nov 10, 2014
Under visual studio, this is a typical run time error,
Code:
void func(int x){
x = 3;
}
int main() {
int x;
func(x);
}
When x is passed to the function func, it is not initialized. But my question is that why it should be an error? On the other hand, if I change the definition of func a little bit like this,
Code:
void func(int& x) {
*x = 3;
}
int main() {
int x;
func(&x);
}
Now in main, x is still not initialized, but this time there isn't a run time error like "the variable is being used without being initialized. Why?
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Apr 22, 2014
I am having trouble getting the cout statements that I commented out to work properly. And I can't figure out why the first movie in the movies.txt file displays at the end of the list in my output screen when it should only display once as the first item. I am also having trouble figuring out where and how to set up the static variable.
Purpose : This assignment requires that you to develop a program using the classes listed above. Specifically you will build a hash table containing movie data. The collision strategy will be to build linked lists as the array elements.
Program Specifications : Your program will read the data from the file named Movies.txt located in the StudentFiles1.zip file on the Connections Portal. Each record contains 2 fields separated by a space. They are:
FieldsData Type
Motion Picture Association Code (MPAC)Integer
Movie NameString
Your application program will read each record, create a Movie structure instance and place that structure instance into the hash table.
You will need to modify the appropriate code to provide for an audit trail of the hash table construction. To accomplish this, you will use cout statements in the above class member functions. You will need to modify them to include couts, but the modifications will be relatively small. If not, you are doing it wrong. The hashing algorithm to use is:
Index = int ( 0.618033 * MPAC) % size
Make the array size a constant and set it to 10.
Include a counter for the number of collisions that occurred in building the hash table. Including a static variable in the LinkedList or List class is the best method for doing that.
See the sample audit trail below for the first 5 records on Movies.txt and the size of the hash table set to 3. This is shown for illustration only. The full file will have different locations calculated.
1101-Casablanca is being added
The hashed location is 2
There was no collision loading 1101-Casablanca
------------------------------------------------
1200-Duck Soup is being added
The hashed location is 0
There was no collision loading 1200-Duck Soup
------------------------------------------------
[Code] ....
After the above is displayed, prompt the user to enter the MPAC of a movie to locate. Produce an audit trail when locating the requested movie as shown below: Make sure you list all movies that have collided at the hashed location. That may also cause you to modify one of the existing ADTs a little.
Will search for 6601
at the hashed location is 2
There was a collision here with 6601-Wizard of Oz
There was a collision here with 1101-Casablanca
retrieved from hash table: 6601-Wizard of Oz
[Code] ....
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May 14, 2015
I'm currently working on a program that calculates shipping charges. However I'm stuck, whenever I compile the program the total amount at the end always comes up as my flat rate variable and not the total calculated number.
Code:
#include <iostream>
#include <iomanip>
#define FLAT_FEE 5
using namespace std;
int main() {
double num, pound, ship;
ship = FLAT_FEE;
[Code] ....
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Mar 27, 2015
In Visual Studios I keep getting this error. cpp(36): error C4700: uninitialized local variable 'Eligible' used
Code:
#include <iostream>
#include <string>
#include <iomanip>
#include <fstream>
#include <cmath>
using namespace std;
void Getinput(int& Loantype, double& Income, double& Totaldebt, double& Loanamount);
[Code] ....
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