boost库 set初步使用

boost库提供了一种容器叫做侵入式容器，侵入式容器与stl库提供的容器有所不同；侵入式容器的使用减少了数据之间的拷贝。。。。。

#include <boost/intrusive/set.hpp>
#include < iostream>
#include < utility>
#include < string>
using namespace boost::intrusive;
using namespace std;
class animal{
public:
int _legs;
set_member_hook<> _set_hook;
animal(int legs) : _legs(legs) {
}
~animal() {
std::cout << "legs = " << _legs << std::endl;
std::cout << “I am ~animal” << std::endl;
}
bool operator<(const animal &a) const {
return _legs < a._legs;
}
};

int main () {
std::cout << “Hello Boost” << std::endl;
animal a1(1);
animal a2(2);
{
typedef member_hook<animal, set_member_hook<>, &animal::_set_hook> hook;
typedef set<animal, hook, constant_time_size< false>> animal_set;
animal_set animals;
animals.insert(a2);
animals.insert(a1);
std::cout << "size = " << animals.size() << std::endl;
for (const animal &a : animals) {
std::cout << "legs = " << a._legs << std::endl;
}
auto begin_it = animals.begib();
animals.erase(begin_it);
std::cout << "size = " << animals.size() << std::endl;
}
}