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file input: get() after seekg()

Posted on 1998-07-12
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Last Modified: 2010-04-10
After a file is traversed with get() I use seekg() to return to the beginning of the file.  This works okay, but when I use get() after I reach the beginning of the file, get() just doesn't get it (so to speak).  I don't understand this.  Here is some sample code compiled with DJGPP (hope it shows correctly):

#include <iostream.h>
#include <fstream.h>

main()
{
  char nextChar;
  ifstream readIn("gallery.txt");

  if(!readIn)
  {
     cout << "Can't find the file \"gallery.txt\"" << endl;
     return 0;
  }

  while(readIn.get(nextChar))
  {
    cout << nextChar;
  }

  cout << endl << "Place before seekg(): " << readIn.tellg() << endl;
  readIn.seekg(0, ios::beg);
  cout << endl << "Place after seekg(): " << readIn.tellg() << endl;

  cout << "=====================================================" << endl
       << "=====================================================" << endl;

  while(readIn.get(nextChar))
  {
    cout << nextChar;
  }

  return 0;
}

How do I get input from the second readIn.get()?  Why is it not inputting?  Is there something I'm doing wrong?
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Question by:faehntim
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2 Comments
 

Accepted Solution

by:
mehlert earned 100 total points
ID: 1167598
Set up your while loops like this:

  while(readIn.peek() != EOF)
  {
     readIn.get(nextChar);      
     cout << nextChar;
  }

You need to peek for the end of the file instead of getting it.
-Matt
0
 
LVL 2

Expert Comment

by:mlev
ID: 1167599
This happens because the end-of-file flag is still set for readIn.
Do readIn.clear() to clear it (before or after seekg()).
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