C :: Create File To Write Text And Read Back The File Content

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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C/C++ :: Create And Write To Text File And Then Read From It?

Mar 26, 2014

I have looked through te tutorials here, and even google it, as well as tried to follow the power points from my class..but I still can't seem to figure out how to make this code work correctly.. Basically I have to create a file called grade and write to it a student name and their grade score, and then read from the file all students names and there grade and display this on the screen as well as calculate the grade average for all of the students and display it.

Well I am able to write to the text file, but I can't seem to get the rest to work. I can't figure out how to read from the text file..Here is my code below.

write a sample code that does something similar write to text file string and numbers and then reads from it.

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

[Code].....

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C++ :: Getline - Get Text File And Read Only First 100 Lines Of Text Content

May 31, 2013

I am trying to get text file and read only first 100 lines of the text content using c/c++. how can i do it?

is it something like string line;
getline(stream,line);

??

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C++ :: How To Read All Content From A Text File Into A String

Sep 24, 2013

I'm trying to read all content from a text file into a string. This is the code I'm using for it (I know there are other, maybe better ways to do it but I'd like to stick to this for now):

char* buffer;
std::string data;
FILE* fp = fopen("textfile.txt", "rb");
if (!fp) {
printf("Can't open file");

[Code] ....

So my problem is that I get an exception when I try to free the memory -> 0xC0000005: Access violation reading location 0x51366199

I even get the exception when I try to free it immediately after calloc() but why this is.

And if I use buffer = (char*)malloc(lSize); I don't get any exceptions.

So, why this fails and what I'm doing wrong.

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C++ :: Open A Text File Then Read Data And Print It Back?

Nov 5, 2013

I am in an "intro" C++ course and am having trouble with a section of my current project.

We are required to open a text file, read the data from that file, and print it back.

However, we are supposed to let the user input the name of the file that is to be opened. This is the code I have so far. It is not opening anything.

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
const int NUM_QUESTIONS = 30;
typedef char CharArray[NUM_QUESTIONS];
string fileName;

[Code]...

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C++ :: Read From A Txt File And Then Write A New Text File With Sorted Line

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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C/C++ :: How To Create A Txt File - Read / Write And Open For More Information

Jan 25, 2015

How do i create a text file read and write in it but every time i reopen the program i must not override the data in the text file .

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C :: Original Text File / Generate Another File With Text Content In Upper Case

Nov 29, 2014

Code software that, from an original text file, generate another file with the text content in upper case.For exemple:

entrence:

luke
tom
alex

outings:

LUKE
TOM
ALEX

My code so far:

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
}

[code]....

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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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C++ :: How To Save Struct To File And Then Read It Back From The File

Aug 5, 2013

How to save the struct to file and then read it back from the file ?

Code:
#include <conio.h>
#include <stdio.h>
struct student {
int person;
int egn;
float AvergeGrade;

[Code] ....

Have average grade: %f", person[i].FirstName, person[i].LastName, person[i].egn, person[i].AvergeGrade);
}
//Save to file
getch ();
}

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C :: Appending Content In Middle Of A Text File

Sep 18, 2013

A user enters a query and other users reply to it. But it creates a problem here. After adding queries, if I wish to reply to query in between then it adds a redundant entry in file. 1st entry is the original query without reply and 2nd entry is the same query now with a reply added. I want only 1 entry of the query along with replies.Here is the code:

Code:

#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
#include "var.c"
int check_count();
void add_query();
void add_reply();
}

[code]....

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C :: Write Text Up To 1000 Characters And Get It Back

Jun 20, 2013

I'm challenged to write a code for the following:

write a text up to 1000 characters, and get it back. the end of the text is detected though EOF on a new line or reaching 1000 characters.(EOF=ctr-Z on a new line)

I mainly have problem how to bring the EOF work probably. it doesn't react when I press ctrl-z directly?

Code:
int i;
char Text[1000];
printf("write the text:
");
gets(Text);
for(i=0;i<=1000;i++){

[Code] .....

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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++ :: Read From Txt File One Bit At A Time And Then Write Into Binary File

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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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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C :: Read / Write To File

Mar 3, 2013

How can I erase the data stored in /tmp/a.txt after every run of this code?

Code:

#include <stdio.h> // IO operations
#include <unistd.h> //for pid, ppid, fork functions
#include <sys/types.h> //for pid_t type, kill function
#include <stdlib.h> //for exit function
#include <signal.h> //for kill function
#include <sys/types.h>
#include <sys/stat.h>

[Code]...

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C++ ::  Write Hex In Text File To Other File

Jul 28, 2014

getting hex from a text file and writing it to a different file. I made a program to dump hex from files into a text file and now I need it to save the hex to the original file. Here is my code to save the hex:

int main(int argc, char * argv[]) {
ofstream myFile;
ifstream file(argv[1], ios::in);

[Code].....

It never outputs the correct contents of the file that has been dumped. I've checked with other hex editors and the hex dumper is working correctly.

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C :: Opening File - Read / Write

Aug 5, 2013

this is my read/write functions based the read from the last post! then went nuts with it! used the %19s%*s on the write to the file, solved all the probs on the read side! but any refining on this would be great. This is another program that i started with the forums, and started going my own direction!

Code:

void WriteAccount(int account,char *a[])
{
FILE *fptr;
char Memo[20];
char buff[20];
double Amount;
struct tm *sTm;
}

[code]....

the a[] is a string array with bank account names, and Account is the number on the menu based list.

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C++ :: Read / Write From File (fasta)

Dec 10, 2014

I'm looking to write a program in C/C++ to traverse a Fasta file formatted like:

>ID and header information
SEQUENCE1
>ID and header information
SEQUENCE2

and so on

in order to find all unique sequences (check if subset of any other sequence) and write unique sequences (and all headers) to an output file.

My approach was:

Prep: Copy all sequences to an array/list at the beginning (more efficient way to do this?)

Grab header, append it to output file, compare sequence for that header to everything in the list/array. If unique, write it under the header, if not, go on.

However, I'm a little unsure as to how to approach reading the lines in properly. I need to read the top line for the header, and then "return?" to the next line to read the sequence. Sometimes the sequence spans more then two lines, so would I use > (from the example above) as a delimiter? If I use C++, I imagine I'd use iostreams to do the reading.

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C/C++ :: How To Read And Write Certain Characters From A File

Oct 12, 2014

How to read some characters from file, I know we can move a pointer to some position using seekg() & seekp() function, get current position of the pointer through tellg() & tellp() functions. By moving the pointer to appropriate position using seekg(), we can read the whole line using getline() function. But is there any function which read certain characters from the current position of the pointer and write certain characters from current position of the pointer.

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C++ ::  How To Read And Write Certain Characters From A File

Oct 12, 2014

How to read some characters from file, I know we can move a pointer to some position using seekg() & seekp() function, get current position of the pointer through tellg() & tellp() functions. By moving the pointer to appropriate position using seekg(), we can read the whole line using getline() function. But is there any function which read certain characters from the current position of the pointer and write certain characters from current position of the pointer.

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C++ :: Read And Write The Values Of File?

Sep 22, 2012

the output of the password text file contains like this:

username
776655443322 (password encoded)

How to write the value in last line (3rd row) of the file. after that read and write or alter 3rd row value. I need logic using "C" language.

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C++ :: Read File Content Line By Line

Jan 23, 2015

I am reading my file (20GB) line by line using boost like this

PHP Code:

boost::interprocess::file_mapping* fm = new boost::interprocess::file_mapping("E:Mountain.7z", boost::interprocess::read_only);
boost::interprocess::mapped_region* mr = new boost::interprocess::mapped_region(*fm, boost::interprocess::read_only);

 char* bytes = static_cast<char*>(mr->get_address()); 

An exception is thrown in the second line while allocating memory for mr.

I use boost because it can also work in Mac which my code will be ported to.

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C# :: How To Create Event To Notify And Save / Write Information To File

Feb 24, 2014

I am writing a program that models the ups & downs of a particular stock. Everything is pretty much done, except that I need to create another event to notify that saves the following information to a file when the stock's threshold is reached: date & time, stock name, initial value & current value. I have something like this so far:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

[Code]...

I feel like i need something along the lines of

s.stockEvent += new Delegate( ???? ) in my myFile class so it know when the threshold is reached, to write the information of the current stock to the file.

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C :: How To Read And Write A File Using Serial Port

Dec 29, 2013

Explain me a working code to read and write a file using serial communication.and i need to store that file.I know normal file handling in C, but how it is through serial port i am not getting.

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C :: File Write And Read As A Function Error

Sep 27, 2014

called object 'fptr_in' is not a function or function pointer
called object 'fptr_out' is not a function or function pointer

what can i do for the errors?(i mustn't use loop and arrays for the code)

Code:

#include <stdio.h>
void sum_of_2nd_and_3nd( FILE* fptr_in, FILE* fptr_out);
int main()
return 0;
}
void sum_of_2nd_and_3nd( FILE* fptr_in, FILE* fptr_out){
}

[code].....

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