Greetings,
>> As far as I recall I have seen the %20s a few places in the code,
>> might just be misrememberance. :o)
> $ egrep '%[0-9.]+' *.c | wc -l
> 62
Guess my memory isn't as bad as I used to think. :o)
> I remember the first time I ever saw 'cout' after sprintf. I was (and still
> am) very unimpressed.
I won't argue that cout/ostream is nicer to use than the printf
family, because, imho, it's usually easier to see the construction
of what you want to output, which isn't always crystal clear when
you use complex output operations with lots of setw, setprecision,
etc. manipulators.
However, the benefit of cout over the printf-family is... type
safety and overloading. :o)
Consider this:
short s = 37;
int n = 38;
fprintf(fp, "%d %d", s, n); // fp being a FILE*
fout << s << ' ' << n; // fout being a std::ofstream
This is a rather simplistic example since short is automatically
promoted to int and whatnot, but use your imagination for the more
complex example. :o)
However, the iostream capabilities do not come to their full right
until we look at an example where we want the representation of
something when written to always be the same - an obvious choice to
look at as an example would be outputting a matrix:
std::ostream& operator<<(std::ostream& os, const Matrix& m) {
for (int i = 0; i < m.rows(); ++i) {
for (int j = 0; j < m.cols(); ++j) {
os << m.at(i,j) << ", ";
}
os << std::endl;
}
os << std::endl;
return os;
}
Normally, with a few changes, we would reproduce the double
for-loop every time we want to print a matrix (the apt pupil would
most likely wrap this in a few functions) - however, the force in
the iostream library lies in the inheritance, so with just the
above code we can do all of this:
Matrix m<4,4>; // creates a 4x4 matrix
std::cout << m;
std::ofstream fout("outfile.txt");
fout << m;
fout.close();
We could even send it to char_data (if we make it inherited from an
ostream), and the representation would still be unchanged.
> My biggest gripe with *printf() is when you have a
> typedef that varies what it is in your format string. The whole 'need a
> big enough buffer' thing isn't so great but you can use snprintf() to work
> around that because it tells you how much space it needs (unless you're
> using GNU C library 2.0, ick).
Double ick to that library. :o)
And it is rather lovely to have std::string, std::stringstream and
likes at your disposal. :o)
--
Yours truly,
Henrik Stuart (http://www.unprompted.com/hstuart/)
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