removing duplicates from a c++ list

I have been looking for an effective solution to remove duplicates from a C++ list.

The list consists of pointers to a class object which has an attribute ID. I want to remove duplicates based on that ID.

for my purpose, the unique method of the STL list will work in which we can pass a BinaryPredicate. i.e.

void unique( BinPred pr );

I searched on the internet about how to use this method, n got an example in which we can declare a function returning boolean and use the "name" of that function as Binary Predicate.

But it's not working.

What actually is this binary predicate and how do i use it ? ... Any help will be appreciated. Here is the code snippet:

class SP_MDI_View {
..
..
bool removeDupli(SP_DS_Node*, SP_DS_Node*);
bool DoReductionGSPN(SP_DS_Node*, SP_ListNode*, SP_DS_Node*);
..
..
}
SP_MDI_View::DoReduction( ... ) {
 SP_ListNode setZ; // typedef list<SP_DS_Node*> SP_ListNode, where SP_DS_Node is some other class
 setZ.clear();
 setZ.merge(tempsubset);
 setZ.merge(setX);
 setZ.push_back(*cs_iter);
 setZ.unique(removeDupli); //Error here
}
bool SP_MDI_View::removeDupli(SP_DS_No开发者_开发百科de* first, SP_DS_Node* second) {
return ( (first->GetId())==(second->GetId()) );
}

You could write a function like:

bool foo (int first, int second)
{ return (first)==(second) ); }

Also, you might need to declare the function as static if your using it in class.

You have to use unique on an ordered list. So the first thing that you must do is sort the list.