How do I open a .txt file in C++?

Question

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main () {
  string line;
  ifstream myfile("hey.txt");

  myfile >> line;
  cout << line;
  system("pause");
  return 0;
}

Why does this not print out what is in my "hey.txt" file?

You have to check the state of `myfile`. For example, if it found the file `hey.txt` to open. — Mahesh, Jun 07 '13 at 19:31

score 6 · Answer 1 · edited May 23 '17 at 12:25

6

This should do the job, If you are new to these things please read http://www.cplusplus.com/doc/tutorial/files/

EDIT: in article above .good() is a bad practice, look here if you need to more detail Testing stream.good() or !stream.eof() reads last line twice

// reading a text file
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main () {
  string line;
  ifstream myfile ("example.txt");
  if (myfile.is_open())
  {

    while(getline(myfile, line)) {
      cout << line << endl;
    }
    myfile.close();
  }

  else cout << "Unable to open file"; 

  return 0;
}

edited May 23 '17 at 12:25

Community

1
1

answered Jun 07 '13 at 19:33

varun

4,522
33
28

2

You copy-and-pasted some bad example code. That `while (myfile.good())` loop is a [bad practice](http://stackoverflow.com/questions/4324441/testing-stream-good-or-stream-eof-reads-last-line-twice). – Blastfurnace Jun 07 '13 at 19:46
@Blastfurnace I agree, I'll add the link – varun Jun 07 '13 at 19:49
Instead of `else cout << "Unable to open file";`, is there a way to throw a FileNotFoundException? I'm newbie in C++. – VansFannel Jul 24 '21 at 08:12

How do I open a .txt file in C++?

1 Answers1