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STLPort set::iterator

Started by J_Vitel Dec 23, 2004 at 4:04 PM 0 replies 1.2k views

Original Post

Dec 23, 2004 at 4:04 PM

I've recently moved from Borland C++ Builder 5 to 6 and I found that STLPort's containers such as set and multiset only supports const_iterators. the next is from _set.h:


  typedef typename _Rep_type::const_iterator const_iterator;  
  typedef const_iterator iterator;

In several of my programs, I change properties of many objects wich are stored within a set, so I wonder if is it good idea to modify _set.h in order to make it support non const iterators as the previous version of Borland's STL thanks in advance.

Fruny

203

Fruny

Dec 23, 2004 at 4:14 PM

No. This is normal. Since the value of a set element doubles as its 'key' (unlike map where they are separate, a const key and a non-const value.), you are not allowed to modify set elements in-place: doing so might invalidate the set's ordering properties. If you want to change such an element, you need to remove the original from the set and insert a new one.

If you really know what you are doing, a const_cast can remove the constness.

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