C++ :: Writing Integer Array To File In Binary Form And Reading It

May 30, 2013

Both arrays arr and pointers are the same size. I am having problems reading pointers from file into a new int array.

FILE* ky_pt=fopen("stashedclient","ab");
write(fileno(ky_pt), pointers, sizeof(pointers) );
pointerindex=lseek(fileno(ky_pt), 0, SEEK_CUR );
printf("pointerindex after writing array %d

[Code] .......

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C :: Writing Binary Data Or Reading From A File

Mar 6, 2013

I am having problems either writing data to a binary file or reading from the file. Through the process of elimination I am posting the code where the data is written to file to see if I can eliminate that as an option. I know the data is being processed correctly because, through the use of another function, I can view the data.

I also know that fwrite must be including some padding because the file size ends up being 576 bytes after it is written instead of 540 bytes (the size it would be if no padding is used). Here is my struct:

Code:

typedef struct {
char teams[25];
float wins;
float losses;
float pct;
int runsScored;
int runsAgainst;
} STATISTICS;

Here is where I initialize it:

Code:
STATISTICS stats[12] = {
{"Anaheim Arrays", 0.0, 0.0, .000, 0, 0},
{"Pittsburg Pointers", 0.0, 0.0, .000, 0, 0},
{"Indianapolis Integers", 0.0, 0.0, .000, 0, 0},

[Code] ....

And here is the function that writes my data. The sA array is only used to change the scheduled games based on the variable week.

Code:
void schedule(STATISTICS stats[]) {
FILE *f;
int sA[12], week = 0, runsPerGameA = 0, runsPerGameB = 0, runsAgainstA = 0, runsAgainstB = 0;
int index, a = 0, b = 1, i = 0;

[Code] .....

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C++ :: Writing 32 Bit Integer To 32 Bit Value In Binary

Jul 17, 2013

So, I was reading that article on binary files:

Disch wrote:
u16 ReadU16(istream& file) {
u16 val;
u8 bytes[2];

file.read( (char*)bytes, 2 ); // read 2 bytes from the file
val = bytes[0] | (bytes[1] << 8); // construct the 16-bit value from those bytes

[Code] .....

u32 would be the same way, but you would break it down and reconstruct it in 4 bytes rather than 2.

But, I don't know what he means by the part in bold text.

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C/C++ :: Writing Array To Binary File

Mar 10, 2014

So I'm trying to write an array of integers to a binary file. He's my code:

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

[Code].....

I know that it is an array of characters right now, and I will be using the reinterpret_cast when I finish my program. Anyways, when I run the executable, it only writes 1234 to the file. My assumption was that the sizeof() was not being set properly, but even manipulating that won't fix it.

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C :: Writing Structure Array Bytewise To Binary File And Read It Back

Aug 21, 2014

I would like to write a complete structure array to a file and read it back, recovering all the data. I have tried the following:

Code:

#include <stdio.h>
#include <string.h>
#define NUM 256
const char *fname="binary.bin";
typedef struct foo_s {
int intA;
int intB;
char string[20];

[Code]...

//---------------------------------------------------- but the mac field is reading back some random value repeatedly. Why is that? And how do I fix this?

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C/C++ :: Reading And Writing In Binary Files?

Jun 5, 2014

why I'm giving "Access violation reading location 0x336827B8" and also I was able to read my data but it's giving me weird stuff. I want to write the sorted grades and the average in a new disk file. so here's my code so far here's my code

#include "stdafx.h"
#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>
using namespace std;
int avg(int sum, int size);
void swap(int *, int *);

[code]....

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C++ :: Writing And Reading Binary Data In FORTRAN?

Apr 2, 2013

I am writing a double number in Binary format to the console of program A (in FORTRAN) with the following code:

Code:
REAL*8 A
A = 12.54
INQUIRE(6, name = xstring)
OPEN(1,file=xstring, access='stream',action='write')
WRITE (1) A
CLOSE(1)

And trying to read that number by program B (in C++) which is connected to program A by anonymous pipes. Following is the reading part of program B:

Code:
#define BUF_SIZE 5000
BOOL bSuccess = FALSE;
char Buf[BUF_SIZE];
DWORD dwRead;
for (;;) {
bSuccess = ReadFile( V_hChildStd_OUT_Rd, Buf, BUF_SIZE, &dwRead, NULL);
if( ! bSuccess || dwRead == 0 ) break;
}

Note: V_hChildStd_OUT_Rd is a handle to the output of program A.

After running the program although bSuccess becomes TRUE, Buf array does not include the number (12.54) that I am expecting. If I do the same process without using the binary format it works fine and I can read the number. I know somethings wrong with the writing or reading of binary data but I do not know what it is.

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C++ :: Reading And Writing Variable Binary Width Data

Mar 8, 2013

How to read and write an arbitrary number of bits from/to a file stream.

For instance, how to repeatedly read 9 bits from a file, then change to 10 bits, then 11 bits, and so on?

Obviously one way is by doing a lot of bit shifting, and masking. But honestly, I'm too dumb to get it right. Then I thought about using std::bitset and std::vector<bool>.

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C :: Writing Array Into File And Reading Array From File

Apr 20, 2014

i've been trying to write array into file and read them into the same program again, but the output is all wrong.

Code:

#include<stdio.h>
int main()
{
FILE *fp;
char name[3][7];
int x;
}

[code]....

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C++ :: How To Convert Large Valuge Form Single Integer To Array

Jun 3, 2013

i have mathematic operation and the result is near 70 digits....single variable cannot hold it....

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C++ ::  writing Binary Data On Txt File?

Aug 16, 2013

I a want to write a code to convert a string into binary data for that i wrote a code its working perfectly but there is one problem , some of the binary data is written in 7bit and i want to convert it to 8 bit by adding 0 to the last.

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

[Code]....

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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 :: 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 :: 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++ :: 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/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

public:

BitInputStream(istream& s) : in(s), buf(0), bufi(8) { }
/** Read the next bit from the bit buffer.
* Return the bit read as the least significant bit of an int.
*/
int readBit(){
int i;
if(nbits == 8){
buf = in.get();

[Code] .....

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C++ :: Program Crash Writing To Binary File

Feb 17, 2014

cant write to binary file

#include <stdio.h>
#include <stdlib.h>
typedef struct {
int number;
} something;
void main() {
int numbers[10]={1,2,3,4,5,6,7,8,10,12};

[Code] .....

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C++ :: Writing In Binary Format Array Of Unsigned Int Values

Aug 5, 2013

I am trying to write down in binary format an array of unsigned int values but i get the following compilation error :

: In function ‘int CIndex(std::fstream&, std::fstream&, std::fstream&, std::fstream&)’:
./src/IndexBuilder/index.cpp:23:26: error: no matching function for call to ‘std::basic_fstream<char>::write(int*, long unsigned int)’
./src/IndexBuilder/index.cpp:23:26: note: candidate is:
/usr/include/c++/4.6/bits/ostream.tcc:184:5: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::write(const _CharT*, std::streamsize) [with _CharT = char, _Traits = std::char_traits<char>, std::streamsize = long int]

This is the part the is not working:

Code:
// uia is : unsigned int * uia;
// then I have allocated the space for it
// load it with unsigned int's
// k is the number of variables in my array

o.write(uia,sizeof(unsigned int)*k); But thsi should be so simple and strait forward.... in c i do it as :

Code:
fwrite(uia, sizeof(unsigned int), k , fp); but since i would need to convert fstream to FILE* i decided to do it c++ way.

and this is how i opened the file :

Code:
o.open (fileName.c_str(),std::ios::out|std::ios::binary);

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C++ ::  Reading And Writing To File Using Same Fstream

Oct 16, 2013

I have a file of data where each line consists of 4 parameters (degree, alpha, beta and x) and a value corresponding to these, organized in increasing order of the parameters. Here's the test file I'm using:

0 1 1 0.5 3.5
1 1 1 -0.5 -0.5
1 2 0 0.2 4.5
1 3 0 0.2 -4.5
2 0 0 1.5 2.1
2 1 0 0 5.6

My code is supposed to look for a certain set of parameters (currently set to 1 2 1 1.5, which is not contained in the file) and its value. If it's there (i.e. the file contains the value for the right parameters) the program is done. If not it should calculate the value using a function JacobiPoly() and insert the wanted parameters and corresponding value in the appropriate place in the file.

I have a code in which I think everything works except the writing to file. I use an fstream so I can both read and write and open it with ios::out||ios::in. I'm also aware I need something similar to fseek in between input and output but according to [URL] .... reading and writing to the same file using the same fstream, seekp() should suffice. I'm using seekp(), but the output (in the form inout << (...)) doesn't work.

Here's the code:

fstream inout;
inout.open("inouttest.dat", ios::out | ios::in);
int degree=1, readDeg;
double alpha=2, beta=1, x=1.5, value, readAlpha, readBeta, readX, readVal;
bool foundVal=false;
streampos beforeRead=(streampos)0;

[Code] ....

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C/C++ :: Reading And Writing PPM File Image

Dec 7, 2014

I am attempting to read a ppm file. When i do it i try to write it back in another file just to see how's done and i get a terrible result. I assume the problem is something with the casting i do to the variables.

This is my image class

Image:: Image(unsigned int width, unsigned int height, bool interleaved) {
buffer = new Component [3*width*height];
this->height=height;
this->width=width;
this->buffer=Component();

[Code] .....

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C++ :: Writing Text Data To A Binary File With Fstream

Jul 9, 2014

fstream ifs;
ifs.open ("data.str", ios::binary | ios:ut);
char *data1 = "data1";
char *data2 = "data2";
ifs.write(data1, strlen(data1));
ifs.write(data2, strlen(data2));

when i this,data2 is not going under data1, i thought each write starts on a new line?

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C++ :: Reading And Writing Data In Text File

Jan 5, 2015

Code to write data(Double type e.g 12345.67891) in text file like pattern given below. Remember to put tab between each column.

-----------------------------------------------------
Column1 Column2 Column3
Value 1 Value 2 Value 3
Value 4 Value 5 Value 6
Value 7 Value 8 Value 9
----------------------------------------------------

& Also how to read data from this file.

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C++ :: Reading / Writing File On Multiple Threads?

Aug 7, 2013

I'm currently working on a server for handling clients in a 2d online game and I wrote some regular fstream file code for handling the file that stores their information and I was about to implement it into the server, then I realized there might be a problem having it open multiple times concurrently, so I googled it and came up with
posts like

[URL]

I'm wondering if I can just treat it like everything else or will I have to do something specific for opening on multiple threads?

p.s. I did read those posts but I'm very new to multithreading

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C++ :: Reading File Then Writing To It If Duplicate Not Found

Jan 22, 2014

I'm having issues with writing to a file. more precisely, i'm trying to determine if a set of numbers are in the file. if they are already in it, don't write to the file. if not, write to the file. My problem is my program is writing all numbers, even duplicates. The sort is working.

#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
//Counter Stats
int STR;

[code].....

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C++ :: Writing Data On A File In Binary Mode Multiple Times

Oct 20, 2013

When you have to write data on a file in binary mode multiple times (without closing the file), is the put pointer left where you ended writing the last time, or do you have to use tellp() or seekp() again and again to make sure you write at the right place?

I would have the same question about the get pointer, does he stay in place after you're done reading something (without closing the file, of course), or do you have to set it back at the right place with seekg() ??

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C++ :: Reading GLOBE File - Access Violation Writing Location 0x00000001

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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