why this program is incorrect?

[Andy]

Hi,

I am trying to get the iterator that points to the last element of a
deque.
However, the following program is incorrect:

#include <deque>
#include <iostream>
using namespace std;

int main()
{
deque<int> queue;
deque<int>::iterator it;

queue.clear();
queue.push_back(5);
it = queue.rbegin().base();

cout<<"*it = "<<*it<<endl;
return 0;
}

How can I get a correct one?
Thanks a lot!

Andy

 

[Andy]

well, it = (queue.rbegin() + 1).base() will work.
andy

 

[Dietmar Kuehl]

I am trying to get the iterator that points to the last element of a
deque.

/**/ std::deque<int> queue;
/**/ queue.push_back(5);
/**/ std::deque<int>::iterator it = queue.end() - 1;

 

[Clark S. Cox III]

well, it = (queue.rbegin() + 1).base() will work.
andy

Why even bother with reverse iterators? Why not just use:

it = queue.end() - 1;

 

[Andreas Andersen]

Hi,

I am trying to get the iterator that points to the last element of a
deque.
However, the following program is incorrect:

#include <deque>
#include <iostream>
using namespace std;

int main()
{
deque<int> queue;
deque<int>::iterator it;

queue.clear();
queue.push_back(5);
it = queue.rbegin().base();

cout<<"*it = "<<*it<<endl;
return 0;
}

How can I get a correct one?
Thanks a lot!

Andy

Hi,

base() returns an iterator one beyond the element pointed to by the
corresponding reverse_iterator so you need

it = --(queue.rbegin().base());

instead.

/Andreas