Visual C++ :: File Writing With Onsavedocument

Oct 15, 2012

Code:
void CFileMgm::write(string fname, solutions databox) {
file1.open (fname.c_str(), ios::out);
if (file1.is_open())//if(file)+ {
file1<<"Population Size is : ";
file1<<databox.pop_size;

[Code] ....

I don't know why this code is unable to write any thing in file. Following is onsavedocument function

Code:
BOOL CTspGeneticAlgoDoc::OnSaveDocument(LPCTSTR lpszPathName) {
string filename = (string) lpszPathName;
CFileMgm mydatafile;
mydatafile.write(filename,sol);
return CDocument::OnSaveDocument(lpszPathName);
}

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Visual C++ :: Writing Structure To CSV File Won't Work

Jan 23, 2013

I need to compute some values, place them in a structure containing two vector variables, and save them in a CSV file. Right now, I can't even generate a file. I wrote the structure definition and file writing code in a header file (after first borrowing it). I have a "button" that is supposed to trigger all of the activity. I'll attach the code below:

HEADER
________-----_______------
#ifndef EINSTEIN_H
#define EINSTEIN_H
#include <stdio.h>
struct SizeAll{
int year;
double R;
};
int write_to_file(int count, struct SizeAll *data, char const *fileName)

[code].....

My grasp of pointers and how and when to use them evaporated long ago.

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C :: Visual Studio 2012 - Writing Data Into TXT File / How To Stop Reading Char

Feb 23, 2013

I am using visual studio 2012.....in below code i m writing data in to a test.txt file but i dont know with which key file stop accepting char...i tried ctrl+z and ctrl+d but not working ....

Code:
#include<stdio.h>
#include<conio.h>
main(){
char ch;
FILE *ptr;

[Code] ....

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Visual C++ :: File Stream Change Its Address During Writing Text Contents To The Stream

Apr 29, 2013

I wrote a program to write text contents to file stream through fputs, the file stream address was changed in the middle of writing text content to the stream (11% text content have been put into the file stream), that cause the file stream pointer can be evaluated problem and raise exception on stream validation code in fputs library function, my question is what things could go wrong to make file stream pointer changed its address to something else or a NULL pointer if the file stream have not been flushed and closed.

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C :: Writing A Simple File / Text Parser To Read A Config File

Feb 6, 2014

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:

Code:

readlength=2500000
start=0
finish=25000000
cutoff=20000
samplingfreq=250000
poles=10
filterpadding=500
}

[code]....

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.

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Visual C++ :: Reading / Writing Registry In Windows 7?

Feb 19, 2013

I have a 32-bit application that I've been maintaining for about 12 years and it runs on every Windows platform up to Windows 7. In all that time I've been using CWinApp::GetProfileXxxx() and CWinApp::WriteProfileXxxx() calls to read and write my program settings (about 70 settings) in the Registry. The settings are read from the Registry at start-up and written to the Registry when the program closes. There is also a method for the user to read and write the program settings to an INI file using the same code as the Registry access.

On my Windows 7 system the Registry read/write works just like it always has on all previous Windows versions. However, on some customer's Windows 7 machines there appears to be a problem with the Registry access. The program settings are either not being read from the Registry or are not being written to the Registry. I think the settings are not being written - but I don't know that. When the user uses the INI file the settings appear to be read and written.

The customer has complained a bit (I'd complain too) but doesn't have the time or doesn't want to take the time to run some simple tests for me to find out what's going on with his Windows 7 system.

So here is my question: Are there any user account settings or permissions that can block the program's access to the Registry? He claims he is an Administrator but I can't even get him to verify that.

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Visual C++ :: Writing To HKLM Registry In Windows 7?

Jul 8, 2013

When I write to the Windows 7 Registry at HKEY_LOCAL_MACHINE, I get a return code of 5 which is the "access denied" message when I execute RegCreateKeyEx.

This happens even if the User has administrator rights.

How can I tell Windows 7 to allow the program to write to the registry?

The application is a 32-bit application and it should be allowed to run in either a Windows 7 32-bit or 64-bit machine.

I noticed that when I run certain popular programs, a User Account Control dialog box comes asking:

"Do if you want to allow the following program from an unknown publisher to make changes to this computer".

Should my application call User Account Control and if so, how do I do it in C++ Visual Studio 2008?

I also found out that 64-bit Windows machines have two registry hives. Is there a different code to handle the same task?

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Visual C++ :: Writing Formula For Standard Deviation?

Apr 17, 2013

How to write a formula for standard deviation but im having a hard time ?

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Visual C++ :: Writing A Lexical Analyzer / Parser

Oct 6, 2012

I'm trying to learn more about how Lexical Analyzers/Parsers work. I haven't coded any classes yet, because i'm not really sure how the entire process from a Lexer to working code goes.

My goal is to write a simple made up programming language and translate that to another language, like Javascript. The first thing i have to do is give the code to a Lexical Analyzer.

The lexer will split the source into tokens and assign a label to it. So suppose i have the following code:

Code:
def myVar = 10;

The lexer will split that into token like this:

Code:
def -> keyword
myVar -> Identifier
= -> Operator
10 -> Number

That's basically as far as i understand what a lexer does. How can i translate the tokens to a language like Javascript? From what i understand i need to write a Parser class. But i couldn't find any info on what that class exactly does. So what is exactly the next step i have to take?

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Visual C++ :: Writing And Reading Char Bytes?

Jun 26, 2013

I have used the following code to write and read wchar_t bytes from a disk file:

Code:
int WriteBytesW(wchar_t * wcp, int nsz, wchar_t * wcfilepath) {
wfstream wf;
codecvt_utf16<wchar_t, 0x10ffff, little_endian> ccvt(1);
locale wloc(wf.getloc(), &ccvt);
wf.imbue(wloc);

[Code] ....

Output:

save bytes succeeded
1234 5678 9ABC EF12 ABCD FE21 DCBA 1F2A EFFF 02FF
read bytes succeeded
nsz =: 20

Now, if wbuf[8] = 0xefff; is replaced by wbuf[8] = 0xffff;

Output:

save bytes succeeded
1234 5678 9ABC EF12 ABCD FE21 DCBA 1F2A 02FF
read bytes succeeded
nsz =: 18

Obviously, the 0xffff wbyte is not read. WHY ?

This presents a significant problem when attempting to read ALL wbytes from a file.

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C :: Computing Grades From Input File And Writing To Output File

Aug 31, 2014

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.

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C++ :: Can Edit Text File Without Writing Content Of Whole File Again

Mar 28, 2013

Can i edit records stored in file without rewriting whole file again .?

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Visual C++ :: Reading And Writing Values From Excel Spreadsheet

Jul 31, 2013

I just got a job programming a windows application. One of the requirements is reading and writing values from an excel spreadsheet. Looking online, it appears that C++ isn't the best (one of the worst?) languages for reading and writing values from excel files. Now the language I'm most familiar with is C++ and I've been looking at C#, and it appears to be much easier to read excel files.

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Visual C++ :: Writing A Function That Sort Elements Of Array In Numerical Order?

Oct 17, 2014

I have to write a function called sortMe that sorts the elements of an array in numerical order from highest to lowest values (descending order) or vice versa (ascending order).

The assignment asks to: NOT re-arrange elements in the array; instead, it uses a second array, an array of indexes for the elements in the original array and then sortMe sorts the second array based on the values in the original array. A sorted version of the original array can then be produced with these sorted indexes.

Header of the function sortMe must be as shown below:

void sortMe(int array[],int sortedIndexes [], int size, char mode)

When mode is 'a', the function sorts the array in the ascending order, and when mode is 'd', the function sorts it in the descending order.

Declare and initialize the array array.

Declare the array sortedIndexes but do not initialize it. You are going to play with the array sortedIndexes in the function sortMe.

EXAMPLE:

int array[5]={3, 5,-1,10,0};
int sortedIndexes[5];
sortMe(array,sortedIndexes, 5, 'a');

After the function call, the elements of the array sortedIndexes should be: 2,4,0,1,3.

notice that the function does not e-arrange the elements in the array.

Code:
#include <iostream>
using namespace std;
void sortMe(int[], int, char);
void main() {
int arr[6] = { 14, -5, 5, 0, 22, -99 };

[code]...

how to use the other array.

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Visual C++ :: Enable Writing To And Reading From Files - Unresolved External Symbol

May 13, 2013

Perhaps this can be a very popular error,

Code:

#include <stdio.h>
#include <tchar.h>
#include <iostream>
#include <string>
#include <fstream>// enable writing to and reading from files
#include <cstdlib>
#include <time.h>
using namespace std;
class Person {

[Code] .....

Error list:

Code:

Error 1 error LNK2019: unresolved external symbol "void __cdecl saveperson(void)" (?saveperson@@YAXXZ) referenced in function _main H:Cry_DevProgrammingC++Using_class_ in_ c++Using_class_ in_ c++Using_class_ in_ c++.obj
Error 2 error LNK2019: unresolved external symbol "void __cdecl displayperson(void)" (?displayperson@@YAXXZ) referenced in function _main H:Cry_DevProgrammingC++Using_class_ in_ c++Using_class_ in_ c++Using_class_ in_ c++.obj
Error 3 error LNK2019: unresolved external symbol "void __cdecl editperson(void)" (?editperson@@YAXXZ) referenced in function _main H:Cry_DevProgrammingC++Using_class_ in_ c++Using_class_ in_ c++Using_class_ in_ c++.obj
Error 4 error LNK1120: 3 unresolved externals H:Cry_DevProgrammingC++Using_class_ in_ c++DebugUsing_class_ in_ c++.exe 1

What I can do to fit this problem?

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Visual C++ :: Writing To Named Pipe Coming From A Service (session 0) Without Admin Rights

Dec 9, 2014

I'm trying to write to a named pipe created by a service, as we all know the session 0 isolation implemented in vista and forward makes this task a bit complicated.

well at this point i managed to make almost all to work but my real problem comes when i try to write on the named pipe from my GUI application with no administrator rights

If i run the GUI application with admin rights it works 100% but, I don't need that application to require the user admin rights and for security reasons i rather to leave it without admin...

so i started my research and i found that there is a way to achieve this by calling CreateNamedPipe() with a low integrity security attributes...

well how to implement but i finally made it, the problem is that it gets worse than passing null security attributes, it works with admin rights with NULL security attributes, but when i pass the low integrity security attributes it gives "access denied" even when using admin rights, so i guess im passing the wrong security attributes but how to manually create the security descriptor string.

This is the code:

Service (session0) SERVER

Code:
DWORD WINAPI PipeThreadRSVS(void* pParameter){
LPTSTR _PIPE_NAME = "\.pipeRSVHPipeIn";
bool Break=false;
char Received_Buffer[BlockSize+16];
DWORD BytesRead = 0;

[Code] ....

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C++ :: Writing New Line To File

Sep 9, 2014

I am executing below sample program

Code: #include<iostream.h>
#include <fstream.h>
using namespace std;
int main()

[Code]......

when i am counting the lines using wc command it is giving 1 instead of 2.

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C++ :: Reading And Writing Bit To A File

Nov 3, 2014

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:

BitInputStream(istream& s) : in(s), buf(0), bufi(8) { }

[Code] ....

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C# :: Writing To A File (Not Replacing)

Dec 11, 2011

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;

[Code] .....

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C :: Writing A Struct To A File

Sep 28, 2013

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 .

Code:
// initialize the structure struct->x = 0, struct->y = 0
File *fp = fopen("filename", "r+");
struct MYSTRUCT mystruct = (struct MYSTRUCT*)malloc(sizeof(MYSTRUCT))

//check
fread (mystruct, sizeof(MYSTRUCT), 1, fp);

// 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....

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C :: File Reading And Writing

Sep 19, 2013

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.

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C :: Writing New Line In A File?

Oct 4, 2014

I have a problem writing new line in a file. So far, this is my code.

Code:

fprintf(f, (ctime(&mytime)));
fprintf(f, "%s %s %d %d", item, brand, price, amount);
fprintf(f, "
");
fclose(f);

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C :: Reading And Writing To File

Mar 19, 2013

Code:
#include <stdio.h>
struct hardware{
int recNum;
char toolName[30];
int quant;
double cost;

[Code] .....

I'm having issues with my functions working properly. I'm not sure where I'm going wrong with them and if i'm using the correct mode for the fopen.

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C++ :: Writing Float Value To File

Oct 11, 2014

I'm trying to write the value of xcord to the file, but it's come out as jiberish like š™ for some reason.

#include <iostream>
#include <Windows.h>
using namespace std;

[code]....

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C++ :: Reading And Writing To The Same File?

Apr 30, 2013

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'm just using basic fstream.

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C++ :: Writing Some Classes Into A File

May 28, 2013

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....

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