i want to read text between two indices in the file using file i/o operations in c++. HOw can i do it? for example, here is the text file:
1:
..
..
2:
..
..
3:
..
..
4:
in this text file i need to print only the lines between 2: and 3:. How could this be done?
I am trying to read lines from a .txt file like this:
// "file.txt"
This is the first line.
This is the second line.
To do this, I tried using the following code:
int main() {
std::ifstream data;
data.open("file.txt");
[Code] ....
The output I want is:
This is the first line.
This is the second line.
However, all I am getting is:
This is the first line.
I can't quite see why this isn't working. I am decently familiar with file streams in C++, so I thought I would know what I was doing, but apparently not.
The first part of the exercise is to read the lines from a file placing each line into an array. I thought my code looked correct however nothing but garbage prints out. Here's my code.
#include <iostream>
#include <fstream>
#include <string>
[Code]...
Program background: Ticket Sales Details You will sell tickets in advance and at the door. Prices for buying in advance and at the door will be given. Also, the total number of tickets sold in advance will be given. Each guest will have a unique number. If there are n tickets sold in advance, then these guests will be numbered 0 through n-1. As the event starts, requests to buy tickets at the door may be made and these guests will be numbered sequentially, starting at the lowest unassigned number. The maximum number of guests will be 1000. The first line of the file contains the following three values, separated by spaces: Cost of the presales tickets (in dollars), Cost of the tickets at the door (in dollars), and the number of presale tickets. The first two values will be positive real numbers to two decimal places and the last will be a positive integer.
The second line of the file will contain one positive integer representing the number of auction items followed by a positive real value to two decimal places (at most) representing the minimum bid increment, in dollars. The first value is guaranteed to be 1000 or less and the second will be in between 1 and 50, inclusive.
The third line of the file will contain all the prices of the auction items, in dollars, separated by spaces, in order. Thus, the first price is the price of item 0, the next price is the price of item 1, and so on. These values will be real numbers represented to up to 2 decimal places.
The fourth line of the file will contain the three following positive integers pertaining to the raffle: the number of raffle tickets available, the cost of a raffle ticket in dollars, and the number of raffle prizes. (It's strange to have raffle tickets that don't cost a whole number of dollars.)
The fifth line of the file will contain each of the values of the raffle items, in dollars, separated by spaces, in order. Thus, the first price is the price if item 0, the next price is the price of item 1, and so on. These values will be real numbers with upto 2 decimal places.
The sixth line of the file will contain ten positive integers representing the number of each of the drinks 0 through 9, in order, that are in stock.
The seventh line of the file will contain ten positive real numbers with upto 2 decimal places representing the price of each of the drinks 0 through 9, in order.
The eighth line of the file will contain a single positive integer, numEvents, representing the number of events that occur at the charity ball. These events are split into two groups: actions by guests at the ball and awards given (raffle, auction, person, totalrevenue). All of the actions precede all of the awards. You will produce exactly one line of output for each event described. Here are the formats of each event that could occur:
If a patron buys a ticket at the door, a command will be on a line by itself:
BUY TICKET k
where k is a positive integer indicating the number of tickets bought at the door. These guests will be numbered as previously mentioned. You are guaranteed that the total number of tickets bought, including presales, will not exceed 1000. This is what I have so far and I cannot figure out why it wont calculate the total revenue. I am not completely sure if it is even accessing the if statement in main.
Code:
#include <stdio.h> #include <stdlib.h>
#include <string.h>
#define N 1000
[Code].....
lets say this is our textfile
-----------------------------------
45(here is space)string and other shit is here
454(here is space)string and other shit is here
4121(here is space)string and other shit is here
77(here is space)string and other shit is here
45545(here is space)string and other shit is here
1122(here is space)string and other shit is here
-----------------------------------
how do i get exactly that number in every line start? and compare but i jus tneed to get them to variable so ?
how to read random lines from a text file using "C", without repeating same lines.
View 10 Replies View RelatedI have a file that I need to read in blocks. I need to read in n lines at a time, do some processing, and then read in the next block of n lines until the file is done. I know the size of the block, but not the number of lines in the file unless I check that first. Normally I would read in like,
Code:
// declarations
string new_input_line, input_file;
// create an input stream and open the input_file
ifstream input_file_istream;
input_file_istream.open( input_file.c_str() );
[Code] .....
// process through data_block
With this approach, I'm not sure how I would keep looping to read the next block until I hit the end of the file without knowing how many lines are in the input file. I could process the file to find that out, or get that number from bash and pass it it as an argument, but it seems like that shouldn't be necessary.
I could also read in and store the entire file as a vector of string and then process through it afterwords, but that would not be a very efficient use of memory.
I'm trying to read in lines for a file and storing it in an array. This is what I have so far. Am I allocating the memory correctly?
Code:
typedef struct {
/* declartion of variables */
} App
typedef struct {
[Code].....
How do I access the array content? I'm suppose to strtok the contents from the lines stored in the array and use it again.
Simple program to convert files to XML files. However I am trying to narrow down why my code is not working. I am reading a line that looks like "2001 Joe Dirt Los Angeles", then the next few lines are followed by text and the the fifth line looks like "---End of Description---".
So here is the file
2001 Joe Dirt Los Angeles
Home is where you make it
Best movie ever(but not really)
But seriously
---End of Description---
Here is example code to test the process
string line;
while(dataFile >> line) {
getline(dataFile, line);
cout << line << endl;
}
My returning output is
[space]Joe Dirt Los Angeles
[space]Home is where you make it
[space]Best movie ever(but not really)
[space]But seriously
My test code is skipping the date on the first line but replacing it with a space. Then it is skipping my fifth line which reads "---End of Description---". Now if I take the code out of the while loop and hard code in five lines of output (x5 getline(dataFile,line); cout << line << endl;) then my code works as expected. I get all of the information. Date and the fifth line.
It looks like when I am testing for the EOF it is also taking in the numeric value at the beginning of the first line. However, that does not explain why it is dropping that fifth line.
What I have to do is write a small program in C++ to parse the symbols that are used on 5 different lines of text in each position until position 30 is reached on each line. The goal of the parsing program is to interpret the symbols (characters), if there are any per each position, on the 5 lines of text in order to output the actual data that the group of symbols represents.
My question for is this: Is there anything special from a C++ environment that should go in to something like this outside of using standard stuff like the math associated with the search algorithm that has to happen here? The symbols are located in a file, so I know I have to include "iostream" and a few other headers. But outside of header inclusions and the code necessary to iterate and streamline the search and interpretation process, am I missing anything special that I couldn't otherwise find through simple google searches?
Well, I have a .txt file that contains, together with a few characters, columns of values that I want to save in different files like is written in the program (file 1, file2, file3 - a with x, b with y, c with z). BUT, I don't want the values from the lines with the saying "interpolated_vector" to be printed in any of the three files.
What I have is the code below, that has the code that creates the three new files with the columns of values that I want. It is working fine!
Code:
#include <malloc.h>
#include <stdio.h>
#include <stdlib.h>
int i, count;
double *a, *b, *c;
double *x, *y, *z;
char tag[5][255];
[Code]...
I've tried and tried, but couldn't make it work properly. I could only erase one line with "interpolated_vector" using fgets, but all the other lines below this were printed into the three new files (file1, file2, file3).
How I would go about counting lines from a file at the same time as extracting words? I need to know the line number to output what line the word is misspelled on. I tried getline and using sstreams but I could not get it to work.
void SpellCheck::checkValidWords(const string& inFileName) {
string eachword;
ifstream istream;
istream.open( inFileName.c_str() );
if ( !istream.is_open() ) {
[Code] .....
I am trying to read lines from a CSV file and put the values into vectors. The CSV contains a large amount of data and I would like the program to only read certain lines from the CSV into the vectors. An example of the data is below. In my code the user inputs a secid. I would then like the code to only read lines from the csv where the secid matches what the user inputs. The secid's are also not in order so I can't just use a while loop.
My current code is below the data.
secideffect_datecusip ticker
10131014MAY19972313510 AMZN
10131008MAY19982313510 AMZN
10131028NOV20002313510 AMZN
10131023JUL20012313510 AMZN
10196601JAN199663858510 NB
10196601OCT199806605F10 BAC
ifstream infile3("filepath.csv");
if (!infile3) {
cerr << "Couldn't open file!"<<endl;
return 1;
[Code] .....
I want to read certain lines from a file. Let say if the line contains word "makes", the line will be loaded on the screen.how to modify this code.
// reading a text file
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main () {
string line;
[Code] ....
I was assigned to modify Game Lobby code. All the data can be saved in txt file and can be displayed when running the code..How can i remove or delete the certain lines of a txt file when running the cmd?.. I cant program it to be able to delete certain lines but i manage to program to delete the entire data, which is not what i want..
Here's the code so far...
#include <iostream>
#include <fstream>
#include<vector>
#include<cstdio>
#include<iomanip>
#include <string>
using namespace std;
class Player {
public:
Player(const string& name = ""): m_Name(name), m_pNext(0) {}
[Code] ....
I need a way to count lines in a .dat file using fscanf. I must use a regex to check that the characters in the file are alphanumeric. In essence I need to count the ' ' character. I know fscanf ignores this character. I need to exit if it detects anything other than alphanumeric with the digit that is "problem" along with the line number. My .dat file is:
Code:
howard jim dave
joe
(
Maggie My fileCheck.c is: Code: #include "main.h"
int fileCheck(FILE *fp)
{
int ret_val;
int line_count = 0;
char file[BUFF];
[Code]...
The output I am getting is:
Code:
file opened Digit: ( is not an alphanumeric character on line: 5 Program will exit! File closed As you can see, the character "(" is not on the 5th line but the 3rd. It is the 5th "string."
I also wanted to show the regex I am using.
Code:
#define to_find "^[a-zA-Z0-9]+$"
How this can be accomplished?
it looks like a popular method for determining the total lines in a file is to read the entire file character by character in search of ' '. I have a file with 5 lines, but for some reason this code isn't finding any instances of ' '. Is this possible? Is there a better way to get the number of lines in a file?
The file looks like this:
Code:
NAME: John
FRIEND 1: Steve
FRIEND 2: Andrea
FRIEND 3: Ken
OCCUPATION: Programmer
Code:
FILE *f = fopen(currentFile, "r");
if (f == NULL) perror ("Error opening file.
");
int ch, lines = 0;
while(!feof(f)){
[Code] .....
I'm trying to load a file that look like this:
IP:123.123.123.123
Port:12345
I can't figure out how to load multiple lines. I tried using , but I can't get it to work. Is there a better way of doing it than I am right now? This is my code.
char message[100];
int messageCount = 0;
for(unsigned int i = 0; i < file.size(); ++i) {
message[i] = file[i];
[Code] ....
For a project we are given a file with a couple of thousand lines of values, each line having 9 different numbers.
I want to create a for/while loop that, for each loop, stores the 8th and 9th integer of a line as a variable so that I can do some calculations with them. The loop would then move onto the next line, store the 8th and 9th numbers of that line as the same variable, so that I can do the same calculation to it, ending when I've run out of lines.
My problem is less to do with reading the file, I'm just confused how I'd tell it to take only the 8th and 9th value from each line.
My task is to write a function for borrowing books form library called borrow(name,surname, student_id, book_id), which will connect information of borrowed book's ID and student's information in the file.
File looks like this:
John Jackson 45 0
Michael Gregory 34 56
Ann Cawitch 23 0
Chris Lamb 34 50
...
First two words are name and surname of students. First number represents student's ID and second one represents ID of book. If ID of book is 0, it means that student hasn't borrowed book yet, so he can borrow some book. If ID of book is not 0, it means that student can't borrow a book until he returns the old one. So, when student borrows book, ID of book in file should change from zero to some number
This is my code:
void borrow(string name, string surname, int student_id,int book_id ) {
string a;
string b;
int c=0;
int d;
fstream f2;
f2.open("students.txt", ios::out |ios::in);
[Code] ....
Whenever I call function (for example borrow(John, Jackson,45,15)), I get answer "Student isn't sign up library."
Am I on a right path? How to make this code to work?
I am working on a problem for the CS50 online course through the Harvard web site. I am trying to re-size a bmp image. They gave us a small program that copies a bmp image and we are to modify it to re-size the image. Here is the page [URL]..... Any way I am trying to move the file position indicator backwards so I can read the same line from the input file. So I can resize the file vertically I have the image resized horizontally but it keeps over writing the same lines vertically.
/**
* bmp.h
*
* Computer Science 50
* Problem Set 5
[Code]...
I was trying to make a function that would return how many lines are in a certain file. I was looking at [URL] which talks about how to count how many characters are in a text file. I just want the number of lines with in a file.
View 2 Replies View RelatedI am working on a program that deletes same lines in a text file. I already wrote it, but it still doesn't work.
Code:
#include <stdio.h>
main(){
FILE *f1,*f2;
char oneword[100],filename[25];
int c;
long int i,j;
char *norstring[500000]; /* I count from 1 */
[Code] ....
how can i input lines at a specific area in my file. please provide code
View 3 Replies View RelatedI have to txt files, and want them to read into an array line by line and after then a split the lines with delimeters, at the first file I use ";", at the second file I want to split the lines to single words by spaces. My aim is to get the first word from the first file and compare with all the words from the other file, to check is there any matches.
My problem is, that at the first file works everything fine, and I want to do the with the second file, but after reading the lines into lines_input[], I check the an empty = null line, I get segmentation fault.
You can see the code below:
Code:
#include <stdio.h>#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
//Change the
[Code] .....
I am supposed to write a program that reads lines from files and see if the first character is an odd number, if so it will out put the remaining characters to output file, else itll seek to the beginning of the next line, this is what i came up with but its not working as it should, im not sure if its the version im using or the program I wrote, the commented part below was another algorithm I was trying to use.
#include<fstream>
#include<iostream>
using namespace std;
int main() {
char c;
int i =0;
[Code] ....
My text file was as follows:
input.txt
3Ali
4Sami
6Rashid
3Aya
output was unexpected , although some was relatively write but not as I wanted...
