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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Oct 5, 2013
I need to read a text file which has various lines containing integers. I need to write those integers separately in a vector. Example, the first line of the text file contains 3 9 8 7 6 so vector[4]=3, vector[3]=9, vector[2]=8 and so on. Next read the second line 4 1 2 3 4 5 and write to another vector vector[5]=4, vector[4]=1...
I tried the code below but it will write from the second line, the whole line in one vector index.
int str; // Temp string to
cout << "Read from a file!" << endl;
ifstream fin("functions.txt"); // Open it up!
string line;
// read line count from file; assuming it's the first line
getline( fin, line );
[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 5, 2013
I have a text file (test.txt) with the following data:
01,05,25,20130728
01,06,25,20130728
01,07,25,20130728
01,08,25,20130728
01,05,25,20130728
01,05,25,20130728
01,05,45,20130728
01,05,65,20130728
01,05,85,20130728
01,05,35,20130728
01,05,25,20130728
01,05,35,20130728
I want to read this to one string called line. So far I have this code:
string line;
ifstream myfile ("/home/Test.txt");
if (myfile.is_open()) {
while (myfile.good()) {
getline (myfile, line);
for (int a = 0; a <= 335; a++) {
cout <<line.at(a);
} }
myfile.close();
}
so far its only printing the first line and then throwing an instance of 'std::out_of_range'
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Aug 16, 2013
I am making a script to read the latest from a text file. It picks up the line by numbytes in fseek, but the data line may vary and numbytes not be accurate, how can I fix this?
And another problem is that the line has, date, time, value, separated by space, how to read that line and put these 3 information in variable?
#include <stdio.h>
#include <conio.h>
int main() {
FILE *arq;
char Line[100];
char *result;
int tam, i;
// Opens a file for READING TEXT
arq = fopen("temp.txt", "rt");
[code].....
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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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Jun 6, 2013
I build this function in my C++ code. I run the on a UNIX box, build HTML file to use in Windows.
In HTML file building code, I have only a string variable hold the contents of this text file (from unix) & add it into HTML file.
The issue is that when I view the HTML file on windows, it shows all the lines in the text file as one line. I think it lost the CRLF.
My question is when I add lines from text file (reading one line at a time) in UNIX, how do I maintain CRLF ( ) in the stringstream variable so that it will display on HTML in Windows properly, all the lines as it is in unix.
I am aware UNIX uses for line end.
string TextFileToString(string filename) {
string line;
stringstream dosString;
ifstream inFile;
[Code] ......
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May 21, 2012
When I read a text file. I'm reading a list of strings in text file, with one string per line. The first line has extra characters in the string, the rest of the lines read are fine, and I can't understand where the extra characters come from. The file format is this...
A
AA
AAN
AAP
AAPL
AAWW
AAXJ
....
...
Code:
std::vector<std::string> strSymbolList;
std::string s = "";
std::ifstream infile( m_strFileSymbols );
while( std::getline(infile, s) ) {
strSymbolList.push_back(s);
}
infile.close();
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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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Apr 4, 2013
I'm given a list of words that need to be read in from a file and then sorted. I was given a certain way to do it .
Code:
#include <stdio.h>
#define MAX 100
void print_ar(char x[][MAX], int size);
int strcomp(char x[], char y[]);
int strlength(char x[]);
void selection_sort(char c[][MAX], int size);
void strcopy(char x[], char y[]);
[Code] ...
Here are some words from the list
school
aibohphobia
lists
alula
bake
cammac
civic
I cannot figure out what is wrong at the moment. .
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Aug 17, 2014
I am trying to read a file line by line and then do something with the informations, so my method looks like this:
Code:
void open_file(char *link) {
FILE *file = fopen(link, "r");
if (file == NULL) {
fprintf(stderr, "Could not open file.
");
exit(EXIT_FAILURE);
[Code] ....
1) The first complain of valgrind is at the line where I use fgets and its telling me (invalid write of size x), but I have allocated my line to 56000 and the read line is shorter, why is there a write size error then :S?
2) at the line where I realloc where I try to shrink the space he's telling me: Address .... is 0 bytes inside a block of size 56000, But I know i need only this space so why is there a write over space error :S??
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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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May 3, 2013
I wrote the below code to find the line with "abc" as my parameter to strTosearch. I expected to the line 1st line but, this function always match the 2nd line. What am I missing here?
I wanted "found" to be "abc def hgi SSS".
Code in main()
String found=GetstringColSamLine("mytext.txt", "abc");
File name - mytext.txt
abc def hgi SSS
abc ppp yyy
string GetstringColSamLine(string routerFileName, string strTosearch)
[Code] ....
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Aug 24, 2013
I can able to get the last line ten chars but i cant get if the last line is null.
here is my code
#include <cstdlib>
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
using namespace std;
int main(int argc, char *argv[]) {
[Code] ....
here with i have enclosed my file where i am pick my last ten chars ...
Attached Files : log.txt (4.8 KB)
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Jul 2, 2013
I have an external file with one column of data. If I have a counter value let say counter =1, and counter++ and so on. How I can write such a c++ code that if the value of counter and value from the external file are same then generate an action let say cout both values i.e. value of counter and value from external file.
for more information, here is an example:
data in file(in one column): 2 6 8 9 10...
value of counter : 1 2 3 4 5 6 7 8 9...
then cout values only if value of counter and value from the file is same.
Here is my code so far, but it does not seem to work;
#include<iostream>
#include<fstream>
using namespace std;
int main() {
const int SIZE = 10; //Size declaration of array
int hours[SIZE]; //Array declaration
[Code]...
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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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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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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 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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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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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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Dec 2, 2013
I have been working on a program to scanfile and whenever it encounters what the user wanted it prints it, and it is all right less the first line of the file that the program jumps,
Code:
#include<stdio.h>#include<string.h>
#include<stdlib.h>
void main()
{
unsigned int j=0 ;
char num[100] , str1[100], str2[100];
FILE *fp;
[Code]....
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