C/C++ :: Delete A Line From A File?
Oct 19, 2014
#include <iostream>
#include <string>
#include <fstream>
#include <iomanip>
[Code]....
assume here the list that i output alice wonderland,8563 capitain jack,842 john carpenter,753leisely chow,421 how do i delete "john carpenter, 753" and rearrange my list in the file like alice wonderland,8563 capitain jack,842 leisely chow,421 i have read about remove function, but it only removes the hole file, but i want to keep the file only modify the lists in the file
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Jun 7, 2013
How can i delete a line from a file created using a C++ program?Can i get a code sample.
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Jan 29, 2015
The program i wrote can run but did not work. I want to delete a line from the textfile "StaffList.txt" but when i cin the name, for example "Ben". After the program ran finished and i open the textfile, the name "Ben" and the whole line is still inside the textfile! I have created the "temp.txt" file before i run the program.
//information inside the "StaffList.txt"
James S1325685J12580
Peter S8856325K52650
Ben S1025639Z85250
Ken S9052365B74100
Marry S9352654I75320
John S7754852H99630
Jenny S7042525L74530
May S1256985G15960
Betty S1135565K56360
Kyle S9545530A1234100
[code]....
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Dec 16, 2014
I'm trying to make a simple phonebook app that can show contacts, add, and delete. I'm pretty new to C++ and fstream functions, deleting a line in my bool erase() function?
#include <iostream>
#include <conio.h>
#include <string>
[Code].....
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Nov 18, 2013
How to use these functions: fread, fclose, fseek, ect.
Q1) Write a program to delete the sixth line in a file. Do not change the sixth line to a blank line; delete it completely.
*** this one I was able to replace the file with what I wanted but realized it needs to be deleted ***
Q2) Write a function that deletes the last line of any file.
*** this one didn't even know where to start ***
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Feb 6, 2014
Some codes to delete a text in a specific line in a text file.
Example:
This is line 1
This is line 2
this is line 3
Removing line 2,
This is line 1
This is line 3
//////////////////
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Oct 14, 2013
I have a text file name fruit.txt that contains the following information of fruit id, fruitName and fruitQuantity.
Code:
1:pear:30
2:apple:20
3:banana:24
4:orange:15
5:watermelon:35
If let's say I key in 2, it will search for the id=2 and delete the whole line and the id of banana which is orignially 3, will become 2 and orange which is orignally 4 will become 3 etc.
I researched on how it can be done and most suggested to put inside a vector and fout the line.
I know how to put the values in the vector but how should I go about searching for the id and if the id is found it will delete that line inside the file.
Code:
ofstream fout;
ifstream readFile("fruit.txt");
while (getline(readFile, line)) {
[Code]....
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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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Sep 25, 2013
So I'm reading a file line by line and storing it backwards into a list. So if the file has has this format...
1
2
3
4
The code should store each line in a list as such...
4, 3, 2 ,1
Instead the code will store the last variable in all nodes. So the final list will look like this...
4, 4, 4, 4
Here is my code...
struct node *head = NULL;
int i;
while(read(in, &i, sizeof(int)) != 0) {
struct node *temp = malloc(sizeof(*temp));
temp->line = &i;
temp->next = head;
head = temp;
}
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Jul 15, 2013
I need to read lines from one file and copy them line by line into another file using dynamic memory allocation. It compiles but gives me a seg fault. Why/How?
Code:
int main(){
FILE *fp1;
FILE *fp2;
FILE *i;
fp1=fopen("file1","r");
fp2=fopen("file3","w+");
[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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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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Apr 12, 2015
Im trying to read from a file, line by line, with no specified number of values in the file. Check out my code:
int main() {
string x;
ifstream fin;
int count = 0;
char ch;
fin.open("CWC_Master.txt");
if(!fin)
[Code] .....
Now, this works great! However, its skipping some lines. And I dont know why. For example: Lets say that the input file is:
superman toy
sm2335
19.99
batman toy
bm5532
25.99
aquaman toy
am6786
26.00
Where it should output the above, instead it outputs every other one. Like:
superman toy
19.99
batman toy
25.99
aquaman toy
26.00
How can I fix my code so that it SIMPLY(i say simply because I am still a beginner coder) can read line by line?
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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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May 12, 2014
I have to read the information about logic gates from a file. The file format is shown below:
Code:
gateOne = NAND(inpA, inpB)
gate2=NAND(1,2)
3 = NAND(23,25,26)
As, it can be seen from the above structure that whitespaces are not same everytime. So, to deal with this situation, i am using boost library to remove all whitespaces from the line which is being read and then try to find the name of gate and its input. My code is given below which is able to correctly find the gate names and its first input...but my code is not able to find the second, third and so on input names.
Code:
//C
#include <stdio.h>
//C++
#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <cstring>
#include <boost/algorithm/string/erase.hpp>
[Code] ....
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Oct 13, 2014
How to read a file line by line and then later access them by doing something like
Code:
lines[0] //Line number one
...
lines[100] //Line number one hundred and one
lines[100][0] //L
lines[100][1] //i
lines[100][2] //n
lines[100][3] //e
lines[100][4] //
lines[100][5] //n
...
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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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Jul 27, 2013
First of all I need to know how to read from file.
Second, I need to read line by line from the file.
For example, the file contains:
8H 3S TH 9D 5S
5D KD 9H 4D 3D
8C TD 5D QS 2C
I wanna use array, so I need to store 8H in array[0], 3S in array[1], until 5S get stored in array[4].
I need to read the first line, the the second, and then the third.
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May 7, 2014
I'm doing a daily time record that record every inputed date on a txt file how will have an option or how will I delete a some of the choosen date? i'm using C++
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Nov 19, 2014
I have to ask the user if they want to delete any records. The user can enter -1 to finish deleting records. I have to write the remaining records in an output file. So, i have this, but
1) it doesn't let me enter more than 1 id, and
2) it doesn't output anything to my output.txt.
records.txt
6
123 Jose Garcia 99
345 Luis Garcia 87
234 Jazlyn Soriano 79
456 Carter Sander 95
567 Natalia Soto 67
789 Isabel Santana 80
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
using namespace std;
class Student {
private:
int id;
[Code] ....
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Dec 9, 2014
I have to manage a Clinic. I need to delete a booking (for example, if John said he's coming on March 22nd at 15:30 but then he say he's not going to come, I have to delete that booking so another person can use it).
idSearched: the id of the person that is not going to come. I have a lot of specialties and each one has a list. So I ask for the speciality to delete the node (the node contains John's booking). If I don't find it, I return (-1). searchSpecByID return a pointer to the list where the speciality is. So head will point to the first node of the list. In nodeToDelete I have the node I want to delete.
The program detects OK when is the first in the list and when not, but it doesn't delete the node.
Code:
typedef struct bookingList{
tSpecialty specialty;
struct nodo* intro;
} tList;
[Code].....
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Jan 12, 2013
How To Delete A Record From binary File - C++ ?
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Oct 16, 2013
So I have this program which read single text file and write in other. Basically read every line then write to another file "this number is n times here + numbers".
How to modify this to store only 1 time the number in second file. What I mean is not like now:
Now output is:
Count of matching numbers in this group: 7
Numbers:
01070400
01070400
01070400
01070400
01070400
01070400
01070400
Is better to be:
Count of matching numbers in this group: 7
Number:
01070400
Code that I use is:
string path = "text.txt";
var result = (File.ReadLines(path)).OrderBy(x => x).GroupBy(x => x);
using (var writer = new StreamWriter("test1.txt")) {
foreach (var item in result) {
string outGrp = String.Format("Count of matching numbers in this group: {0}", item.Count());
[Code] ...
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Nov 19, 2014
I have to ask the user if they want to delete any records. The user can enter -1 to finish deleting records. I have to write the remaining records in an output file. I have this, but 1) it doesn't let me enter more than 1 id, and 2 it doesnt output anything to my output.txt.
records.txt
6
123 Jose Garcia 99
345 Luis Garcia 87
234 Jazlyn Soriano 79
456 Carter Sander 95
567 Natalia Soto 67
789 Isabel Santana 80
Code:
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
using namespace std;
class Student {
private:
int id;
string firstName;
[Code] .....
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Aug 24, 2013
I'm still learning intro to C language. Currently I'm having problem with my code. The task is to ask user to input information about staff and write them into a text file. The problem occur when:
1) output in text/.exe file display random characters.
2) Data obtained from New_Staff unable to pass into Export_Profile.
3) a new output will overwrite the existing information in the text/.exe file
4) the delete function unable to delete correctly after the first time i delete a staff information in text file.
The code is as follows:
#include <stdio.h>
#include <stdlib.h>
void Menu();
void New_Staff();
void Delete_Staff();
void Export_Profile();
[Code] ....
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