Re: STL - erasing from a set

Hello,

I am trying to do a "set difference" operation, to trying to take some
elements (objects) out of a set. I wrote a small sample program to
test it.

--------------------------------------
#include<iostream>
#include<cstdlib>
#include<set>
#include<vector>
#include<algorithm>

using namespace std;

class A {
     public:
     A();
     ~A();
};

A::A() {
     cout<< "Constructing A\n";
}
A::~A() {
     cout<< "Destructing A\n";
}

int main() {

     A a;
     A a2;
     A a3;
     A* ptr_a =&a;
     A* ptr_a2 =&a2;
     A* ptr_a3 =&a3;

     set<A*> set_a;
     set_a.insert(ptr_a); set_a.insert(ptr_a2); set_a.insert(ptr_a3);

     set<A*> set2_a;
     set2_a.insert(ptr_a); set2_a.insert(ptr_a2);

     cout<< "Before erase\n";

     set_a.erase(set2_a.begin(), set2_a.end());

     cout<< "End of main\n";
     return 0;
}

--------------------------------------

The idea is that set_a should contain only ptr_a3 after the "erase"
operation. Instead, what I get is:

Constructing A
Constructing A
Constructing A
Before erase
Segmentation fault

What am I missing? According to the STL documentation for "set",
deleting a range should be a valid operation.