C :: Read Contents Of A File Using Low I/O Read Statements
May 15, 2013
I want to read the contents of a file block (512 bytes) by block using low I/O read statements. Each record is 64 bytes long and has a pre-defined structure. The first 4 bytes are an unsigned integer; the next 20 bytes are ascii text, etc.
I have a buffer which I can access with buf[0] to buf[63] to read the first record and then buf[64] to buf[127] for the second, etc. However, I was wondering how to map a record so that I can refer to an integer as an integer and a float as float, etc. I can't create a struct and move the 64 bytes to it, as I will have alllignment/padding problems.
What is the standard way to deal with records in C?
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Jan 8, 2014
How can I read contents of a file from the last character? Can I use a loop?
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Jan 30, 2015
I need a sample program to read contents of any xml file using CPP.
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Aug 2, 2014
read a text file and store the file contents into a 2D array?
100 101 102 103 104 105
106 107 108 109 110 111
112 113 114 115 116 117
118 119 120 121 122 123
124 125 126 127 128 131
Here's my code:
const int ROWS = 5;
const int COLS = 6;
int array[ROWS][COLS];
ifstream inputFile;
inputFile.open("table.txt");
[code]....
When i run the program and try and display the array, it doesn't work.
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Jan 5, 2015
Need to correct the errors. i've done so far.
#include<iostream>
#include<fstream>
#include<cstdlib>
#include<iomanip>
using namespace std;
int main() {
ifstream fin; char ch; int size=0;
[Code]...
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Apr 25, 2013
I have written the following code but i am stuck. Write a program that will prompt the user for a file name and open that file for reading. Print out all the information in the file, numbering each new line of text.
Code:
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <ctype.h>
int main()
{
char line[81], filename[21], c;
int i = 1;
FILE *inFile;
[code]....
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Feb 10, 2015
am trying to create a service that will try to create a service that will monitor a folder. Whenever a new file gets created, I am trying to read the contents of new file and copy contents (with same file) at a new location.
The problem I am facing is that only first file that gets its name copied and a file created at a new location, but without any contents. The subsequent files do not get created at all.
My Services.cs looks like this:-
public partial class Service1 : ServiceBase
{
public Service1()
{
[Code]....
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Mar 8, 2013
Code:
#include <stdio.h>
#include <stdlib.h>
int main (int argc, char *argv[])
{
char buffer[256];
FILE * myfile;
myfile = fopen("read.txt","r");
[Code]...
I also got an error in printing wherein the data in read.txt is "Hello" newline "World" and my program prints world twice.
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Oct 20, 2014
Goal:
Read contents from a file and use as the size of a 2d array.
Problem:
C2087: Line 27 : "a1" : missing subscript
C2133: Line 27 : "a1" : unknown size
Code :
int rows;
int columns;
ifstream fObject("inputdata.dat");
fObject>>rows;
fObject>>columns;
char a1[rows][columns];
I am not sure why this is occurring, or if there is a better way to do it.
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Dec 5, 2013
I am trying to read enormous binary files (10-100GB) and parse their contents a bit at a time. As part of the process I need to get the size of the file in bytes. The simple solution
Code: fseek(file,0,SEEK_END);
size=ftell(file);
fails because the file size overflows the long int type returned by ftell. I need a long long int.
Is there a reasonably efficient way to do this? The good news is that it only needs to be done once. I suppose I could read it one character at a time until I hit the end and keep count, but that just seems inelegant...
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Dec 8, 2013
Is possible read text form keyboard using read() function? or which is best way in ansi creplace input command form basic language. for numbers and text...
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Jan 21, 2014
I'm working on a program that reads from a .dat file that has names and numbers associated with the name. What the big picture it will be able to take those names and numbers find the avg of certain peoples scores and display these numbers or names who have the highest etc.
So to keep this short in my main I have it call the class and pass "Even.dat" as a char * fname my questions is how do I go about reading this .dat file? I know sorting it will use a sort algorithm which I will be using a bubble sort. But I haven't worked with ofstream and ifstream very much so some tips would be great! Here's an example of what the .dat file contains
David 42
Rebecca 83
Jonathan 79
Matthew 77
Rose 7
Melanie 75
int main() {
StudentStat StatEven("Even.dat");
[code]....
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Dec 9, 2014
I am a learner in C#. I want to read a particular value from the CSV file. I have learned the getting the csv file into a datatable through browsing. See the following code and my CSV file format. The following code displays all the values.... Say, I want to get what is the 'Volume' for 'ID' = 90.
CSV file (IDVolumeName.csv)
ID:Volume:Name
100:5600:A
95:5000:B
90:4500:C
85:4000:D
Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Data;
[Code] ....
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Apr 22, 2013
I have a code for reading a series of data from a text file.The code was shown below I don't know why I can't successfully read file. (Can open successfully)
btw: the text file and source code were located at the same directory.
#include <stdio.h>
#include <stdlib.h>
int main(){
int numOfAtoms;
[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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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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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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Nov 24, 2014
When reading a binary .img why is it when you read it by slurping in the file, then save it to a string and cout, you don't see the binary but random garbage?
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Nov 24, 2013
When I tried to run my code I keep getting a "Segmentation fault".
I am trying to write a code that read from a file and put the data into a structure.
The file look like the following:
2001,ABBIGAEL,5
1994,ABBIGAIL,5
1996,ABBIGAIL,8
1997,ABBIGAIL,13
The file have 31 lines.
Code:
#include <stdio.h>
#include <string.h>
int main() {
/* Define a daydata structure */
typedef struct {
[Code]....
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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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Jul 15, 2013
Ok, I think I got the main idea of the I/O chapter. Though I think I might be oversimplifying the program because I am getting an interesting error.
Goal here is to read numbers from a file and print the numbers with totals for two of the columns and a calculated average for of the totals.
NOTE: The tables for the info from file look a lot better on my end. [QUOTE] seems to mess it up a bit from copying and pasting.
Info from problem:
Car No. Miles Driven Gallons Used
----------------------------------------------------
54 250 19
62 525 38
71 123 6
85 1,322 86
97 235 14
carinfo.txt file:
54 250 19
62 525 38
71 123 6
85 1322 86
97 235 14
program:
Code: updated code
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Dec 7, 2014
I have learnt recently how to use fgetc, fputc, fputs, fgets but still I am not able to figure out how to read values from a file like for example:
12 14 1928 32993932
17 98
166 109 201
These are separate integers & i want to read them and then manipulate these individual integers like going for 2*I1, 4*I2 and so on where I1 and I2 are 12 & 14.
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Mar 6, 2015
I'm stuck on unix system programming and am beginner about it. Assume that there is a directory which X. There are a file(text1.txt) and another directory which is Y in X. Last, there are two files(text2.noExtension) and text3.noExtension) and another directory which is Z in Y. My goal is that read files and enter directories until there is no directory. How to go on. Example:
Code:
#include <stdio.h>
#include <dirent.h>
int main (int c, char *v[]) {
struct dirent *pDirent;
DIR *pDir;
if (c < 2) {
printf ("Usage: testprog <dirname>");
return 1;
[Code]...
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Dec 29, 2014
I'm new with C language. I got task to do . Actually there are 2 points. Both should be done with reading text from file. write down all letters from text in reverse alphabetic order (each letter 1 time).write down all words in random order.
I'm stuck with first point. Below code gives me entire text, but i need unique characters only. Text file contains few sentences.
Code:
#include<stdio.h>
void main( ) {
FILE *in;
int ch;
if ( (in = fopen("test.txt", "r") ) != NULL ) {
[Code] ....
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Nov 19, 2013
How do i read the end of the line in a txt or dat file? I treid using fscanf in a while loop like this
Code:
while(fscanf(pfile,"%c") != EOF && fscanf(pfile,"%c") != '') {
char c = ' ';
fscanf(pfile,"%c",&c);
str += c;
}
The reason why its important to stop after each line is that i need the program to read the data from each line separately.
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Nov 15, 2014
I'm finishing up my first semester as a Computer Science major, but I'm struggling with programming.
I need to read a file into a 2D array.
Here is what the file contains (90 characters):
S
R
R
S
R
R
R
R
S
....
Here is my current code:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
[Code]....
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