Re: [Boost-users] [Min-Max] Usage with a member function as criteria.

1 Sep 2008


      AMDG

Rodolfo Federico Gamarra wrote:
...
Hello Boost users,
I'm working on my thesis with the Boost library (Boost-1.34.1) running on
g++ (GCC) 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2).
What I'm trying to do can be done very simply, but I preferred to do it more
appropriately, I believe, using the Boost Min-Max library. I'm trying to
simultaneously obtain the maximum and minimum values of a member function
call over a lists of objects.
Suppose there exists a
    class utl::Particle;
with a member function
    double GetEnergy() const;
In a member field of another class I have a list of those particles
    std::listutl::Particle particles;
for which I want min/max GetEnergy() values.
How is that accomplished using Boost.Min-Max?
Use minmax_element rather than minmax.

#include 
#include 
#include 
#include <list>

class Particle {
public:
    double getEnergy() const { return(0.0); }
};

int main() {
    std::list<Particle> particles;
    std::list<Particle>::iterator min, max;
    boost::tie(min, max) =
        boost::minmax_element(particles.begin(), particles.end(),
            boost::bind(&Particle::getEnergy, _1) <
            boost::bind(&Particle::getEnergy, _2));
}

In Christ,
Steven Watanabe