Boost C++ Libraries

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Forward Iterator

Description

A Forward Iterator traverses a Sequence allowing movement in only one direction through it's elements, one element at a time.

Notation

i, j

Forward Iterators

I, J

Forward Iterator types

M

An MPL integral constant

N

An integral constant

Expression requirements

A type models Forward Iterator if, in addition to being CopyConstructable, the following expressions are valid:

Expression

Return type

Runtime Complexity

next(i)

Forward Iterator

Constant

i == j

Convertible to bool

Constant

i != j

Convertible to bool

Constant

advance_c<N>(i)

Forward Iterator

Constant

advance<M>(i)

Forward Iterator

Constant

distance(i, j)

result_of::distance<I, J>::type

Constant

deref(i)

result_of::deref<I>::type

Constant

*i

result_of::deref<I>::type

Constant

Meta Expressions

Expression

Compile Time Complexity

result_of::next<I>::type

Amortized constant time

result_of::equal_to<I, J>::type

Amortized constant time

result_of::advance_c<I, N>::type

Linear

result_of::advance<I ,M>::type

Linear

result_of::distance<I ,J>::type

Linear

result_of::deref<I>::type

Amortized constant time

result_of::value_of<I>::type

Amortized constant time

Expression Semantics

Expression

Semantics

next(i)

An iterator to the element following i

i == j

Iterator equality comparison

i != j

Iterator inequality comparison

advance_c<N>(i)

An iterator n elements after i in the sequence

advance<M>(i)

Equivalent to advance_c<M::value>(i)

distance(i, j)

The number of elements between i and j

deref(i)

The element at positioni

*i

Equivalent to deref(i)

Invariants

The following invariants always hold:

Models

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