util::count_iterator< T > Class Template Reference

An iterator dereferencing to a counter value. More...

#include <counter.h>

Public Types
Traits and data types
using	iterator_type = count_iterator< T >
	Type of this iterator. More...
using	difference_type = std::ptrdiff_t
using	value_type = T
	Type of index returned by this iterator. More...
using	reference = T const &
	Type returned by dereference operator. More...
using	pointer = T *
using	iterator_category = std::bidirectional_iterator_tag

Public Member Functions
Construction
	count_iterator ()=default
	Initializes the iterator. More...
	count_iterator (value_type count)
	Initializes the iterator with the specified loop count. More...
Data access
reference	operator* () const
	Returns the current loop count. More...
Modification
iterator_type &	operator++ ()
	Increments the loop count of this iterator, which is then returned. More...
iterator_type	operator++ (int) const
iterator_type &	operator-- ()
	Decrements the loop count of this iterator, which is then returned. More...
iterator_type	operator-- (int) const
Comparisons
template<typename U >
bool	operator== (count_iterator< U > const &other) const
	Iterators are equal if their loop counts compare equal. More...
template<typename U >
bool	operator!= (count_iterator< U > const &other) const
	Iterators are equal if their loop counts compare different. More...

Private Attributes
value_type	fCount {}
	Internal counter. More...

Detailed Description

template<typename T = std::size_t>
class util::count_iterator< T >

An iterator dereferencing to a counter value.

Template Parameters

T	the type of counter returned on dereferenciation

See Also

util::counter()

This iterator returns on dereferencing the net count of how many times it has been incremented. So for example:

std::vector<int> data;
for (util::count_iterator it;; ++it) {
  if (*it >= 10) break;
  data.push_back(*it); // implicit conversion `std::size_t` to `int`
}

this infinite loop will push the value 0 into data on the first iteration, 1 on the second and so forth, until at the eleventh iteration, just before it can push 10, the loop is forcibly broken leaving 10 elements in data.

The iterator can be made to start from an index n different than 0, in which case it behaves like it had already been incremented n times. End iterators can be build in that way too; see also util::counter().

Definition at line 54 of file counter.h.

Member Typedef Documentation

template<typename T = std::size_t>

using util::count_iterator< T >::difference_type = std::ptrdiff_t

Definition at line 64 of file counter.h.

template<typename T = std::size_t>

using util::count_iterator< T >::iterator_category = std::bidirectional_iterator_tag

Definition at line 68 of file counter.h.

template<typename T = std::size_t>

using util::count_iterator< T >::iterator_type = count_iterator<T>

Type of this iterator.

Definition at line 62 of file counter.h.

template<typename T = std::size_t>

using util::count_iterator< T >::pointer = T*

Definition at line 67 of file counter.h.

template<typename T = std::size_t>

using util::count_iterator< T >::reference = T const&

Type returned by dereference operator.

Definition at line 66 of file counter.h.

template<typename T = std::size_t>

using util::count_iterator< T >::value_type = T

Type of index returned by this iterator.

Definition at line 65 of file counter.h.

Constructor & Destructor Documentation

template<typename T = std::size_t>

util::count_iterator< T >::count_iterator ( )

default

Initializes the iterator.

The initial loop count is the default-constructed value of the counter type, which is usually some variation on the concept of 0.

template<typename T = std::size_t>

util::count_iterator< T >::count_iterator ( value_type  count )

inline

Initializes the iterator with the specified loop count.

Parameters

count

the initial loop count

Definition at line 90 of file counter.h.

: fCount(count) {}

Member Function Documentation

template<typename T = std::size_t>

template<typename U >

bool util::count_iterator< T >::operator!= ( count_iterator< U > const &  other ) const

inline

Iterators are equal if their loop counts compare different.

Definition at line 142 of file counter.h.

      { return fCount != other.fCount; }

template<typename T = std::size_t>

reference util::count_iterator< T >::operator* ( ) const

inline

Returns the current loop count.

Definition at line 101 of file counter.h.

{ return fCount; }

template<typename T = std::size_t>

iterator_type& util::count_iterator< T >::operator++ ( )

inline

Increments the loop count of this iterator, which is then returned.

Definition at line 112 of file counter.h.

{ ++fCount; return *this; }

template<typename T = std::size_t>

iterator_type util::count_iterator< T >::operator++ ( int  ) const

inline

Increments the loop count of this iterator, returning a copy with the value before the increment.

Definition at line 116 of file counter.h.

      { iterator_type const old = *this; operator++(); return old; }

template<typename T = std::size_t>

iterator_type& util::count_iterator< T >::operator-- ( )

inline

Decrements the loop count of this iterator, which is then returned.

Definition at line 120 of file counter.h.

{ --fCount; return *this; }

template<typename T = std::size_t>

iterator_type util::count_iterator< T >::operator-- ( int  ) const

inline

Decrements the loop count of this iterator, returning a copy with the value before the decrement.

Definition at line 124 of file counter.h.

      { iterator_type const old = *this; operator--(); return old; }

template<typename T = std::size_t>

template<typename U >

bool util::count_iterator< T >::operator== ( count_iterator< U > const &  other ) const

inline

Iterators are equal if their loop counts compare equal.

Definition at line 137 of file counter.h.

      { return fCount == other.fCount; }

Member Data Documentation

template<typename T = std::size_t>

value_type util::count_iterator< T >::fCount {}

private

Internal counter.

Definition at line 151 of file counter.h.

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The documentation for this class was generated from the following file:

• counter.h