Re: How to use hash_set [a possible solution]

Paulo da Silva escreveu:


....

I found a possible solution. I'm posting it here for others who may need
it but also for comments from experts before I implement it in a real
program.

So, thank you very much for any comments.
Paulo.
__________________________________________________________________________
#include <memory>
#include <ext/hash_set>
#include <iostream>

using namespace std;

class Foo
{public:
    string s; // public for simplicity
    Foo(char *sc): s(sc) {}
};

class eqf
{public:
    bool operator()(Foo const &s1,Foo const &s2) const
    { return (s1.s==s2.s);
    }
};

class hf
{public:
    size_t operator()(Foo const &x) const
    { return __gnu_cxx::hash<char const *>()(x.s.c_str());
    }
};

typedef __gnu_cxx::hash_set<Foo,hf,eqf> MSet;

int main()
{ MSet mc;
    mc.insert(Foo("xxxx"));
    mc.insert(Foo("zzzz"));
    MSet::const_iterator it=mc.find(Foo("xxxx"));
    cout << "xxxx: " << (it!=mc.end()? "present":"not present")
        << endl;
    it=mc.find(Foo("yyyy"));
    cout << "yyyy: " << (it!=mc.end()? "present":"not present")
        << endl;
    for (it=mc.begin();it!=mc.end();++it)
        cout << it->s << endl;
    return 0;
}