Q: STL priority_queue with boost shared_ptr

hi, all
Here is what I want to do: to wrap my self defined class in a
shared_ptr and then insert it into the priority_queue. The
priority_queue should pump the least element of the self defined class
first. To make it simple, here is the toy code.

myClass.h
------------------------------------------
#ifndef MYCLASS_H
#define MYCLASS_H

class myClass {
  public:
        double a;
        myClass(double a) {
            this->a = a;
        }

        bool operator<(const myClass & right) const { //the comparison is
"reversed" in order to pop smallest first
            return a > right.a;
        };
        bool operator>(const myClass & right) const {
            return a < right.a;
        }
        bool operator<=(const myClass & right) const {
            return a >= right.a;
        }
        bool operator>=(const myClass & right) const {
            return a <= right.a;
        }
};
#endif
---------------------------------------------------//over

Foo.cpp
-------------------------------------------------
#include <vector>
#include <queue>
#include <deque>
#include <boost/shared_ptr.hpp>
#include "myClass.h"
#include <iostream>

using namespace boost;
using namespace std;

int main(){
    priority_queue<shared_ptr<myClass> > pq;
    shared_ptr<myClass> temp(new myClass(1));
    pq.push(temp);
    temp.reset(new myClass(2));
    pq.push(temp);
    temp.reset(new myClass(3));
    pq.push(temp);
    while (!pq.empty()){
        temp = pq.top();
        cout<<temp->a<<endl;
        pq.pop();
    }
}
----------------------------------------------------//over

I was expecting the priority_queue to pop 1 first and 3 last. However,
it pops 3 first and 1 last. (If I input 3,2,1 in a sequence, then the
output will be 1,2,3. So it seems that there is no sorting at all) My
real program is more complex than this and I have the reason to use the
shared_ptr. So, directly insert the numbers into the priority_queue is
not a solution. Can someone help me to fix the problem? Thanks ahead.

zl2k