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DescriptionA Forward Iterator is an iterator that corresponds to the usual intuitive notion of a linear sequence of values. It is possible to use Forward Iterators (unlike Input Iterators and Output Iterators) in multipass algorithms. Forward Iterators do not, however, allow stepping backwards through a sequence, but only, as the name suggests, forward.
A type that is a model of Forward Iterator may be either mutable or immutable, as defined in the Trivial Iterators requirements.
Refinement ofInput Iterator, Output Iterator
Associated typesThe same as for Input Iterator
Valid expressionsForward Iterator does not define any new expressions beyond those defined in Input Iterator. However, some of the restrictions described in Input Iterator are relaxed.
Expression semanticsForward Iterator does not define any new expressions beyond those defined in Input Iterator. However, some of the restrictions described in Input Iterator are relaxed.
Complexity guaranteesThe complexity of operations on Forward Iterators is guaranteed to be amortized constant time.
 The restrictions described in Input Iterator have been removed. Incrementing a forward iterator does not invalidate copies of the old value and it is guaranteed that, if i and j are dereferenceable and i == j, then ++i == ++j. As a consequence of these two facts, it is possible to pass through the same Forward Iterator twice.
See alsoInput Iterator, Output Iterator, Bidirectional Iterator, Random Access Iterator, Iterator overview
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