How to move file pointer using gotoxy

This is a discussion on How to move file pointer using gotoxy within the C Programming forums, part of the General Programming Boards category; hi all problem is.. i need 2 extract certain data fields from a text file by simply using file pointer. ...

  1. #1
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    How to move file pointer using gotoxy

    hi all

    problem is.. i need 2 extract certain data fields from a text file by simply using file pointer. I figurd out gotoxy 2 b a way of doin it ..but how do i move the fp and copy the specific text into a local var..

  2. #2
    The superhaterodyne twomers's Avatar
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    So you want to jump to a certain point in a file? I think fseek() is what you're looking for ... http://www.cplusplus.com/reference/c...dio/fseek.html But that is a 1D file pointer setter. Doesn't work in X and Y. If every line in the file was the same length you could flatten an X and Y coordinate to a single offset.

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    ok thanks 4 fseek but dat wud move in one line (row)..as u said. how do i move 2 d next line...and how do i copy d text at d fie pointer location to a local var

  4. #4
    The superhaterodyne twomers's Avatar
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    OK. What you've gotta realise is that carrage returns, i.e. '\n' is also a character. Suppose I have the following file:
    01234
    56789
    with this code:
    Code:
    int main ()
    {
      int i;
      FILE * pFile;
      pFile = fopen ( "myfile.txt" , "r" );
    
      for( i=0; i<10; i++ ) {
        printf( "Position &#37;d has value %d\n", i+1, getc( pFile ) );
      }
    
      fclose( pFile );
    
      return 0;
    }
    You'll notice the 6th position has the decimal value 10. In an ascii graph the 10th element is a new line. It doesn't care about the 2D-ness of the file. It just sees a series of stuff in a line. So if you wanted to move to get the 7, for example, from the file above you'd do something like:
    Code:
    int main ()
    {
      FILE * pFile;
      pFile = fopen ( "myfile.txt" , "r" );
    
      fseek( pFile, 9 , SEEK_SET );
    
      printf( "%c", getc( pFile ) );
    
      fclose( pFile );
    
      return 0;
    }
    fseek( pFile, 9 , SEEK_SET ); The 9 because it starts at 0 and counts the new line.

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