C++ :: Write A Location In A Binary File
Jan 3, 2013
I have a std::vector of short ints that I need to write to a specific location in a binary file (without using .NET code). To that end, I wrote up this code:
Code:
ofstream fileStream (filePathString, ios::out | ios::binary);
int curPos = 2821;
fileStream.seekp(curPos);
int iter = 0;
while (iter < 1024*1024){
char bytesToWrite[2];
//Low byte
bytesToWrite[0] = LOBYTE(dataVector[iter]);
[Code]...
The code runs without crashing, but when I look at the file afterwards in a hex editor, every byte (even those outside the range I thought I was writing to) are replaced with 00. I suspect I'm missing something in my understanding of file streams. Did I write that code correctly? Seekp does move the pointer over the next byte to be overwritten, yes? Am I getting a memory leak somewhere?
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Dec 6, 2013
Following is the program I wrote it basically takes 9 inputs and then save them into binary file. then print out the data stored in binary data and find inverse of it then print the inverse out. but its stuck in a loop somewhere.
Code:
#include <stdio.h>
int main() {
int a[3][3],i,j;
float determinant=0;
int x;
FILE *fp = fopen ("file.bin", "wb");
[Code] .....
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Apr 22, 2013
I am trying to get the code to read from the txt file one bite at a time and then write this bite into the binary file but i cant seem to get it working.
FILE *fpcust, *fpcustbin; //<<<<<-----point to both sales and customers text files, and the new .bin files for both
char buffer;
int ch;
int ch1;
fpcust = fopen("c:customers.txt", "r"); //<<<<-----pointing to the file
fpcustbin = fopen("c:customers.bin", "wb"); //<<<<<-----pointing to the new binary file, opening in writing binary
[Code]...
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Mar 6, 2015
im trying to write an array of struct to a binary the array of struct is filled with data from a text file .
the program gives no errors or warnings but does not write anything at all to the binary file here is the main
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct matches
{
char teamA[20] ;
char teamB[20];
int scoreA ;
int scoreB;
[Code]....
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Oct 11, 2014
I would like to read in binary files, then write them to another file.
I write a code, what works perfectly, if I would like to just copy the file to another. But I want to make it a little other.
If I open a file in hex-editor I also can see the ASCII values. But I would like get the ONLY the hex values to the other file.
For example:
d5 57 4f ad 30 33 0b 4e 49 a7 05 18 c4 90 66 d8 45 ac 39 3e 7d f1 a8 02 80
14 20 90 6e 20 12 38 0c 65 4a 28 d2 80 72 04 20 a9 4a 82 84 60 6a 0b 25
59 4c 30 c8 69 c0 ec fa 36 ed 3a da b1 9a 82 02 e0 bb 7e 41 87 02 f6 10 34
eb 95 93 63 01 6b 8d e1 d7 43 c3 df 92 5d 8a ed 57 61 4e 36 07 2a d7 56 2b
b5 0e 55 83 b4 76 8c b7 61 77 0e c9 76 0c 81 1b 01 63 0c 8b 73 57 d5 6d 4c
0c c2 0d 52 45 18
How could I make it?
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Jan 11, 2015
I have a structure :
struct Entrainement{
string muscleCible, nom, unitesObjectif;
double objectifActuel, dernierObjectif, objectifInitial, capaciteInitiale, progression[10];
};
and I want to write in a binary file the structure. The following works perfectly....
(*pointeurFichierEntrainementBin).write((char*)&exercice, sizeof(Entrainement));
except when the string exceed 11 characters. I guess it's because it has to pick a fixed sized for the string? but what if I want to always be able to have string up to 200 character? because now I can't exceed 11..I know writing a string with c_str() works, but I would like to write/read the structure in one shot.
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Aug 20, 2014
How I write a 0s or 1s to binary file in bits not in bytes how can i do that ???
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Oct 30, 2013
This is what I have so far
My function does not work and my compiler says my int array is not initialized
#include <iostream>
#include <cctype>
#include <string>
#include <fstream>
#include <stdio.h>
using namespace std;
void arrayToFile(ofstream tak, int *arr[], int size )
[Code] ...
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Oct 20, 2013
I have a binary tree, and I want to store all information its leaves stores into a binary file and then read it.
What I tried:
A function that reads the tree, and whenever it finds a leaf, it writes in the binary file:
Code:
[...]
if(tree->right == NULL && tree->left == NULL){
fwrite(tree, sizeof(tree), 1, output);
}
[...] a
And in the main function:
Code:
[...]
for(i=0;i<5;i++){
fread(tree, sizeof(tree), 1, output);
printf("This is the leaf number %d", tree->num);
}
[...]
I'm trying to read 5 nodes just to see if its working but it isn't. The output shows the first node of the tree everytime.
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Jun 24, 2013
So as a learning exercise, I am trying to read and write a binary tree to a file. After googling around, I decided to use a preorder traversal (including null nodes) to write the binary tree to the file. I got stuck trying to read a tree from a file. I can't figure out how to create an unknown number of nodes when they are needed. I could use an array, but that just seems bulky - plus it could run out of space. Is that what I have to do? I've heard of vectors before, but not very much.
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Jan 11, 2013
if i have 2 variables for which values are given by the user,then,does the information get stored into the file in the name of the variable,or just like packs of information.....if the former is true,how to extract the information of a particular variable alone from the whole file?
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Aug 19, 2013
I have my libraries in ../../lib location
and when i try to compile :
gcc -O9 -I ../../include/ -L ../../lib/ -o test test.c thr.o -lm -lthread
I get :
gcc: error: thr.o: No such file or directory
obviously the problem is the library path location but my obj is there
ls -al ../../lib/ | grep thr.o
-rw-rw-r-- 1 xxxxxx xxxxxx 23544 Aug 12 23:03 thr.o
????
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Aug 13, 2013
I'm still reading Prata's book and there is a section where they explain how to write files using the binary mode.
They define a struct
Code: const int LIM = 20;
struct planet
{
char name[LIM];
double population;
double g;
};
planet pl;
And they say you can use the binary mode to write the whole struct at once (in text mode you need to specify every member).
Code: ofstream fout("planets.dat",
ios_base:: out | ios_base::app | ios_base::binary);
fout.write( (char *) &pl, sizeof pl); I don't understand why they use Code: fout.write( (char *) &pl, sizeof pl) instead of just Code: fout.write( pl, sizeof pl)
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Feb 4, 2013
I am planning to use this mostly to copy binary files, but why won't this work with text???
input.txt
int main(int argc, char* argv[]) {
// open file
std::ifstream ifs;
ifs.open("./input.txt", std::ios::binary);
[Code] ....
output.txt
310^?z^@^@^@^@^@300367346^A^@
Will this method always work to copy a file?
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Nov 29, 2014
I cannot write as binary using .dat format in ubuntu, why?
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Feb 19, 2014
#include <stdio.h>
#include <stdlib.h>
int main () {
FILE * pFile;
long lSize;
char * buffer;
size_t result;
pFile = fopen ( "myfile.bin" , "rb" );
[Code] .....
How to open binary for read and write? Why the buffer is char * buffer? i mean in binary u cant read chars . How can it be? how the data is represented? just like txt file? What the buffer will contain how to print this buffer???
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Feb 2, 2014
I'm having trouble opening a file from a specific location.
#include "maidcafe.h"
....
char directory[80] = {"C:UsersPublicDocumentsAnime NotesTransaction"};
char code[20];
printf("Enter file name");
gets(code);
strcat(directory,code);
system("start "" %s",directory);
i thought this would work, but it didn't xD. I got an error
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May 12, 2013
I am trying to write the destructor for my binary search tree. But how to write this.
I have tried
delete root; and delete [] root;
but it doesn't work.
So, here is my code.
#ifndef TREE_H
#define TREE_H
struct PersonRec {
[Code]......
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Oct 30, 2013
My project is to get a file from a designated location in my computer and not just read, but grab the values from the user and make a count, sum, and average calculation of the numbers in my code. I am using the fstream library and I am trying I did do it, I got the values and calcualated them, however I want the values to be accessed from maybe my desktop or my drive, I want to know how to manipulate my code to get a path like C:UserDesktop and maybe executed from the path input or given. I dont know if this is possible, or easy to do. ALso I did copy some of this code from my teachers examples and I dont know exatly why the variables have to be initilized at zero, and I would like to know a little more on the Bitwise right shift breaker used in line 20 something.
Here is my code below.
#include <iostream>//For avergae functionality
#include <fstream>//For the file commands, such as ifstream and the Bitwise right breakers(<< and >>).
#include <iomanip> // To control the amount of decimals in my results desired.
using namespace std;
int main () {
int aNumber=0; //Initilized at zero because of Stack Overflow:
[Code] .....
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Dec 2, 2014
The Problem You are part of a company writing a spreadsheet program. As you know, spreadsheets can be sorted on any column. You're part of the project is to write one binary tree function to sort the data [Hint: use different fields when inserting nodes in the tree.] and a second function to list it in either an ascending or descending sequence. [Note: Each of these functions may actually need to be a set of related functions.]
For sample data you will have a disk file containing information about Shakespeare's plays. Your first function should create a tree based on the sort selected by the user and the second function to display the data in the sequence selected by the user. Regardless of the column being sorted, data in individual records always be displayed in the same line of the output.
Input : Each record will contain the following information: First Performed 9 characters Printed 5 characters Title 26 characters Type 7 characters
Output : Tabular output should be aligned in columns with two spaces between each. All columns should have headings. It should be sorted on the column specified by the user.
Example (This sample data provided so you can test your program.) If the data is:
1595-96 1600 A Midsummer Night's Dream Comedy
1594-95 1623 Two Gentlemen of Verona Comedy
1596-97 1623 King John History
1597-98 1598 Henry IV, Part 1 History
1611-12 1623 The Tempest Comedy
1602-03 1623 All's Well That Ends Well Comedy
[Code]...
Source: [URL]...
Possible outputs are
1 - for a sort by title: First
Performed Printed Title Type
--------- ------- -------------------------- -------
1595-96 1600 A Midsummer Night's Dream Comedy
1602-03 1623 All's Well That Ends Well Comedy
1606-07 1623 Antony and Cleopatra Tragedy
1599-1600 1623 As You Like It Comedy
[Code]....
2 - for a sort by first performed: First
Performed Printed Title Type
--------- ------- -------------------------- -------
1590-91 1594? Henry VI, Part 2 History
1590-91 1594? Henry VI, Part 3 History
1591-92 1623 Henry VI, Part 1 History
1592-93 1623 Comedy of Errors Comedy
1592-93 1597 Richard III History
[Code]....
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Jan 15, 2015
I am working Visual C++ 2012. I am trying to read a GLOBE file using the following code.
#include "stdafx.h"
#include "iostream"
#include <stdio.h>
#include "stdlib.h"
#include "string.h"
#include "cmath"
#include <errno.h>
using namespace std;
/* Conversion useful */
[Code] ....
I am getting the error in the if condition (bold).
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Dec 31, 2014
I would like to copy one bmp file to another using plain fstream (none 3-rd party library). I've managed to come up with something but I keep getting error:
Unhandled exception at 0x504A3442 (msvcr120d.dll) in ConsoleApplication1.exe: 0xC0000005: Access violation reading location 0x00380000.
when i try to write the content of the bmp files not the header, namely error occurs in this line:
Code : ofs_differential.write((char*)&picture, (bfh_warm.bfSize - bfh_warm.bfOffBits));
Also i am not sure if i am doing it in a right way, meaning that even after solving this error i will copy the bmp file successfully.
Code:
// ConsoleApplication1.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <iostream>
#include <fstream>
using namespace std;
struct BITMAPfileHEADER {
unsigned short bfType;
[code]....
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Aug 29, 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 last (2) at 30% each.
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:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
[Code]....
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Mar 15, 2013
The Objective Of This Program Is To Create A File To Write Text And Read Back The File Content. To Do That I Have Made Two Function writeFile() To Write And readFile() To Read.The readFile() function works just fine but writeFile() doesn't.
How writeFile() function Works? when writeFile() function Execute It Takes Characters User Type And When Hit Enter(ASC|| 10) It Ask "More?(Y/N)" That Means What User Want? Want To Go Next Line Or End Input?
If "Y" Than Inputs Are Taken From Next Line Else Input Ends.
But The Problem Is When Program Encounters ch==10 It Shows "More?(Y/N)" And Takes Input In cmd variable.If cmd=='Y' I Mean More From Next Line Than It Should Execute Scanf Again To Take ch I Mean User Input.But Its Not!!! Its Always Showing "More?(Y/N)" Again And Again Like A Loop.
Code:
#include <stdio.h>
void writeFile(void);
void readFile(void);
int main(){
[Code].....
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Jul 8, 2013
how do i decompress an input file and write the results into an output file?
also my do while loop is supposed to keep going unless the user selects the option to exit the program, instead it exits after finishing ay of the options.
here's my code so far...
#include <iostream>
#include <iomanip>
#include <fstream>
[Code]....
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Jun 11, 2014
I have a .txt file which I want to read from and then write a new text file, this time with sorted lines. It is easy to sort one value, but what about sorting entire lines based on one value?
I want to sort the lines based on the FIRST value.
Example text file contents:
values;data
5.01 100
2.9 342
2.69 43534
10.1 43
6.8 45324
Output: Text file containing
2.69 43534
2.9 342
5.01 100
6.8 45324
10.1 43
It's easy to do this if there was only 1 number on each line, but I do I sort all the lines based on the first number in each line?
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