Greetings.
Is there a convinient way to get the next iterator position without mutating
the iterator for non-random access containers? For example,
i + 1
instead of
i++
Thanks 5 5750
Cagdas Ozgenc wrote: Greetings.
Is there a convinient way to get the next iterator position without mutating the iterator for non-random access containers? For example,
i + 1
instead of
i++
Nope. For input or output iterators you cannot even read the same place
twice. I might be wrong, but for forward or bidirectional iterators you may
copy the iterator and increment the copy to "take a peek".
--
Attila aka WW
> Nope. For input or output iterators you cannot even read the same place twice. I might be wrong, but for forward or bidirectional iterators you
may copy the iterator and increment the copy to "take a peek".
That's bad news. The following code would be quite dangerous then:
template<typena me Iterator>
Iterator operator+(Itera tor const& input,size_t offset) {
Iterator output = input;
while(offset > 0) {
++output;
offset--;
}
return output;
}
I can't find a forward_iterato r class to make the above function iterator
type-safe. What's wrong with these STL iterators?
Thanks
Cagdas Ozgenc wrote: Nope. For input or output iterators you cannot even read the same place twice. I might be wrong, but for forward or bidirectional iterators you may copy the iterator and increment the copy to "take a peek". That's bad news. The following code would be quite dangerous then:
template<typena me Iterator> Iterator operator+(Itera tor const& input,size_t offset) { Iterator output = input; while(offset > 0) { ++output; offset--; } return output; }
I can't find a forward_iterato r class to make the above function iterator type-safe. What's wrong with these STL iterators?
You have iterator traits, OMHO you can make a compile time assertion if the
function template is being instantiated with the wrong iterator category.
--
Attila aka WW
> You have iterator traits, OMHO you can make a compile time assertion if
the function template is being instantiated with the wrong iterator category.
Can you give a small example, or give pointers on that matter.
Thanks
Cagdas Ozgenc wrote: You have iterator traits, OMHO you can make a compile time assertion if the function template is being instantiated with the wrong iterator category.
Can you give a small example, or give pointers on that matter.
10 seconds using Google: http://www.roguewave.com/support/doc...ator-traits.ht
ml
--
Attila aka WW This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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