Is there support in C++/STL for sorting objects by attribute?

Question

I wonder if there is support in STL for this:

Say I have an class like this :

class Person
{
public:
  int getAge() const;
  double getIncome() const         


        

Answer 1

I just tried this based on UncleBens and david-rodriguez-dribeas ideas.

This seems to work (as is) with my current compiler. g++ 3.2.3. Please let me know if it works on other compilers.

#include 
#include 
#include 

using namespace std;

class Person
{
public:
    Person( int _age )
        :age(_age)
    {
    }
    int getAge() const { return age; }
private:
    int age;
};

template 
class get_lt_type
{
    ResType (T::*getter) () const;
public:
    get_lt_type(ResType (T::*method) () const ):getter(method) {}
    bool operator() ( const T* pT1, const T* pT2 ) const
    {
        return (pT1->*getter)() < (pT2->*getter)();
    }
};

template 
get_lt_type get_lt( ResType (T::*getter) () const ) {
    return get_lt_type( getter );
}

int main() {
    vector people;
    people.push_back( new Person( 54 ) );
    people.push_back( new Person( 4 ) );
    people.push_back( new Person( 14 ) );

    sort( people.begin(), people.end(), get_lt( &Person::getAge) );

    for ( size_t i = 0; i < people.size(); ++i )
    {
        cout << people[i]->getAge() << endl;
    }
    // yes leaking Persons
    return 0;
}