C++ :: How To Read And Write Certain Characters From A File
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.
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.
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 ) {
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(){
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.
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!
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.
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
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.
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()’:
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.
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;
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.
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?
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;
