How can i read first line from file?

Question

ifstream infile;

string read_file_name("test.txt");

infile.open(read_file_name);

string sLine;

    while (!infile.eof())
    {
        getline(infile, sLine);         
        cout << sLine.data() << endl;
    }

    infile.close();

This program prints all line in the file, but I want to print only first line.

just get rid of while loop and `while (!infile.eof())` isn't correct anyway — billz, Feb 14 '13 at 04:44
Why would you expect a loop to only go through once (unless the condition is set up that way)? — chris, Feb 14 '13 at 04:46

score 20 · Accepted Answer · edited Jan 18 '21 at 14:12

20

while (!infile.eof()) does not work as you expected, eof see one useful link

Minor fix to your code, should work:

  ifstream infile("test.txt");

  if (infile.good())
  {
    string sLine;
    getline(infile, sLine);
    cout << sLine << endl;
  }

edited Jan 18 '21 at 14:12

Zitrax

19,036
20
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answered Feb 14 '13 at 04:52

billz

44,644
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100

No need to call `close` as destructor will do that for you – lets_go_surfing Dec 28 '18 at 02:28

score 2 · Answer 2 · answered Feb 14 '13 at 04:52

You can try this:

ifstream infile;

string read_file_name("test.txt");

infile.open(read_file_name);

string sLine;

while (!infile.eof())
{
    infile >> sLine;
    cout << sLine.data() << endl;

}

infile.close();

This should print all the lines in your file, line by line.

How can i read first line from file?

2 Answers2