About Priority-Queue Constructors

[DingPhonh]

Hi all, I'm having a question about priority-queue. Its constructors are like this:

explicit priority_queue ( const Compare& x = Compare(),
                          const Container& y = Container() );
template <class InputIterator>
         priority_queue ( InputIterator first, InputIterator last,
                          const Compare& x = Compare(),
                          const Container& y = Container() );

So how can I construct an object using the second version. I try like this:

	const int a[] = {1, 2, 3, 4, 5};
	priority_queue <int> MyPQ1(a, a+5);	//Ok
	priority_queue <int> MyPQ2(greater <int>);	//Ok
	priority_queue <int> MyPQ3(a, a+5, greater <int>);	//Error here 

Why is the third declaration wrong???

[DSLq5Di1]

priority_queue <int> MyPQ2(greater <int>); //Ok Also an error.

priority_queue <int, vector<int>, greater<int> > MyPQ3(a, a+5); //Ok