Re: [Dev-C++] How to work with *.txt files??

Ouch.

Don't do that.

There is the vector template class in the stl.

Do not write a method that reallocates all strings every time.

First line - allocate one string.
Second line - allocate two strings.
Third line - allocate three strings.
...

By doing this, you manage to transform a linear operation - proportional
to number of lines in the file - to become O(n^2).

If you open a 100,000 line file, you would perform 100,000^2 / 2 or
5,000,000,000 string assigns.

Never add complexity when it isn't needed.

  std::vector<std::string> strings;

and then

  strings.push_back(line);

or

  strings.reserve(10);
  strings[n++] = line;

is a lot nicer code, and tremendously much more efficient.

/Per W

On Sat, 18 Sep 2004, hielke_prins wrote:

> >> How do I refer to each line of my *.txt file???
>
> /*
>    If you don't have any clue how to read a simple textfile, the first
> thing you
>    proably have to do is buying a good book on C(++). But here ya go.
>
>    I usually read small plaintext files in a vector using a simple
> wrapperclass.
>    Something like this (if you meant to write it in C++ at least),
> didn't test it:
> */
>
> Class Lines
> {
>    string *d_line;
>    unsigned d_nLines;
>
>   public:
>    Lines(istream streamIn);
>    /*
>        (of course you need some simple memberfunctions
>        returning linecount and lines on a given index too)
>    */
> }
>
> Lines::Lines(istream streamIn)
> :
>    d_nLines(0)
> {
>    string inputLine,
>        *tempLine;
>
>    while(getline(streamIn, inputLine))
>    {
>        d_nLines++;
>        tempLine = new string[d_nLines];
>        for(unsigned i = 0; i < d_nLines; i++)
>        {
>            tempLine[i] = d_line[i];
>        }
>        delete d_line;
>        d_line = tempLine;
>    }
> }
>
> Regards,
>    Hielke