Reading file content using read method in c++

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I want to show all content of a text file using “read” method in output.
I have used code below for doing this:

But it was shown some special characters in the end of file content which you can see below:

C++

ÍÍýýýý««««««««îþîþîþ

What’s the reason? I don’t want this.

What I have tried:

C++

#include
#include
#include
using namespace std;

int main(){

ifstream myfile;
myfile.open("c:\\new.txt", ios::in);
myfile.seekg(0, ios::end);
int filesize = myfile.tellg();
char *content = new char[filesize + 1];
myfile.seekg(0, ios::beg);
myfile.read(content, filesize);
content[filesize] = '\0';
cout << content;
delete[] content;
myfile.close();

_getch();
return 0;

}

File content:
this is a test
this is a test

Posted 21-Feb-16 6:40am

Pouria Polouk

Updated 21-Feb-16 23:20pm

Leo Chapiro

v3

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2 solutions

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Richard MacCutchan · Answer 1 · 2016-02-21T07:05:00

Solution 1

That is because you have not added a null character to tell cout where the end of the buffer is. Try:

C++

int filesize = myfile.tellg();
char *content = new char[filesize + 1];  // add space for null character
myfile.seekg(0, ios::beg);
myfile.read(content, filesize);
content[filesize] = '\0';    // mark end of text

Note this code is over simplified.

Posted 21-Feb-16 7:05am

Richard MacCutchan

Comments

Pouria Polouk 21-Feb-16 13:40pm

The problem is still there.
But the number of special characters is decreased!

Richard MacCutchan 21-Feb-16 13:52pm

You must still be doing something wrong, but you need to show us the exact code you are using, and the content of your file (assuming it is only very small).

Pouria Polouk 21-Feb-16 14:00pm

#include<iostream>
#include<conio.h>
#include<fstream>
using namespace std;

int main(){

ifstream myfile;
myfile.open("c:\\new.txt", ios::in);
myfile.seekg(0, ios::end);
int filesize = myfile.tellg();
char *content = new char[filesize + 1];
myfile.seekg(0, ios::beg);
myfile.read(content, filesize);
content[filesize] = '\0';
cout << content;
delete[] content;
myfile.close();

_getch();
return 0;

}

File content:
this is a test
this is a test

Richard MacCutchan · Answer 2 · 2016-02-21T22:52:00

Solution 2

The problem occurs because you are reading a textfile, and as fstream processes the content it replaces CR-LF sequences with the single newline character '\n'. Thus your actual content will be shorter than the length of the file on disk. You should use the getline method to read each line of the file in turn, or set the file type to binary (see ios_base::openmode[^]).

Posted 21-Feb-16 22:52pm

Richard MacCutchan

Comments

Pouria Polouk 22-Feb-16 9:40am

I don't want to use getline method.
thank you so much... solved(ios::binary).