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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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Jan 30, 2014
So I've been turning my programs into classes and I run into errors.
So this program is supposed to allow the user to open the file and either read or write to it.
I've omitted the read part from it as I want to attempt that on my own .
I get these compile errors:
fileclass.cpp:13: error: ISO C++ forbids declaration of ‘choice’ with no type
fileclass.cpp:21: error: ISO C++ forbids declaration of ‘choice’ with no type
fileclass.cpp: In member function ‘int file::choice()’:
[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 28, 2013
So I'm trying to create a program that allows one to read/write on to output.txt. I though I had everything set up right, but its only writing one word to the text file. Heres the code.
#include "stdafx.h"
#include <iostream> //Needed for User Input
#include <fstream> //needed for ofstream
#include <string> // needed for strings
#include <windows.h> //needed for Sleep
#include <cstdlib> //Needed for return EXIT_SUCCESS;
using namespace std;
int main() {
ofstream outputfile; //allows to read and write to files
[Code] .....
If I type Puppies Are Cute and go to output.txt, the only thing written in the text file is Puppies.
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Sep 22, 2012
correct the below code:
file already contains entries : 1st row username; 2nd row password.
check status required to write at third line and need to read or alter the check status value.
Currently this code is working if already there is a value for check status, then it is overwriting else UI hanging.
Code:
WriteCheckStatusToFile(BOOL& locVar) {
FILE *l_pFile = NULL;
CString l_strRememberCheck;
l_strRememberCheck = GetExePath() + _T("password");
CString sVar;
sVar.Format(_T("%d"),locVar);
[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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Jan 16, 2014
int main (){
string filename;
cout << "Enter the file name: ";
cin >> filename;
ofstream myfile( filename.c_str(), ios::app);
}
Here is the code and my original question was how do I make it so that the user can read or write into a file that is not hard coded.
hard code example:
string filename;
cout << "Enter the file name: ";
cin >> filename;
ofstream myfile( "file.txt", ios::app);
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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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Apr 24, 2014
I have a lab with the following instructions:
Manually create an input text file called Lab22BInput.txt with the following data:
Dove
Doe
Alston
Zebra
Egg
Write a program that will read the names from the input file. Print out each of the names read to the screen. The program should go through the list of names and determine which comes 1st in the alphabet. The program should determine how many letters are in this name. Print out the name that comes first in the alphabet and the length of the name.
I have created the input file, and the data correctly outputs to the screen when I run the program. However, I do not know what kind of logic to use to sort them alphabetically and determine the amounts of characters.
So far I have the following:
#include <iostream>
#include <string>
#include <fstream>
using namespace std;
int main()
{
string str1, str2, str3, str4, str5;
[Code]...
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Oct 16, 2013
Trying to read/write from a file located only in the virtual store. Having trouble loading the file in using
outputFile.open("%localappdata%virtualstoreProgram Files (x86)AGC est.txt");
and
outputFile.open("%localappdata%virtualstoreProgram Files (x86)AGC est.txt");
Although I can get it to work using:
inputFile.open("C:UsersNewlanceAppDataLocalVirtualStoreProgram Files (x86)AGCsettingsV5.cfg");
But I need it to work on other machines IE: Not Newlance.
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