24 Ranges library [ranges]

24.6 Range factories [range.factories]

24.6.4 Iota view [range.iota]

24.6.4.3 Class iota_­view​::​iterator [range.iota.iterator]

🔗
namespace std::ranges { template<weakly_­incrementable W, semiregular Bound> requires weakly-equality-comparable-with<W, Bound> && copyable<W> struct iota_view<W, Bound>::iterator { private: W value_ = W(); // exposition only public: using iterator_concept = see below; using iterator_category = input_iterator_tag; // present only if W models incrementable using value_type = W; using difference_type = IOTA-DIFF-T(W); iterator() requires default_­initializable<W> = default; constexpr explicit iterator(W value); constexpr W operator*() const noexcept(is_nothrow_copy_constructible_v<W>); constexpr iterator& operator++(); constexpr void operator++(int); constexpr iterator operator++(int) requires incrementable<W>; constexpr iterator& operator--() requires decrementable<W>; constexpr iterator operator--(int) requires decrementable<W>; constexpr iterator& operator+=(difference_type n) requires advanceable<W>; constexpr iterator& operator-=(difference_type n) requires advanceable<W>; constexpr W operator[](difference_type n) const requires advanceable<W>; friend constexpr bool operator==(const iterator& x, const iterator& y) requires equality_­comparable<W>; friend constexpr bool operator<(const iterator& x, const iterator& y) requires totally_­ordered<W>; friend constexpr bool operator>(const iterator& x, const iterator& y) requires totally_­ordered<W>; friend constexpr bool operator<=(const iterator& x, const iterator& y) requires totally_­ordered<W>; friend constexpr bool operator>=(const iterator& x, const iterator& y) requires totally_­ordered<W>; friend constexpr auto operator<=>(const iterator& x, const iterator& y) requires totally_­ordered<W> && three_­way_­comparable<W>; friend constexpr iterator operator+(iterator i, difference_type n) requires advanceable<W>; friend constexpr iterator operator+(difference_type n, iterator i) requires advanceable<W>; friend constexpr iterator operator-(iterator i, difference_type n) requires advanceable<W>; friend constexpr difference_type operator-(const iterator& x, const iterator& y) requires advanceable<W>; }; }
1
#
iterator​::​iterator_­concept is defined as follows:
  • (1.1)
    If W models advanceable, then iterator_­concept is random_­access_­iterator_­tag.
  • (1.2)
    Otherwise, if W models decrementable, then iterator_­concept is bidirectional_­iterator_­tag.
  • (1.3)
    Otherwise, if W models incrementable, then iterator_­concept is forward_­iterator_­tag.
  • (1.4)
    Otherwise, iterator_­concept is input_­iterator_­tag.
2
#
[Note 1:
Overloads for iter_­move and iter_­swap are omitted intentionally.
— end note]
🔗
constexpr explicit iterator(W value);
3
#
Effects: Initializes value_­ with value.
🔗
constexpr W operator*() const noexcept(is_nothrow_copy_constructible_v<W>);
4
#
Effects: Equivalent to: return value_­;
5
#
[Note 2:
The noexcept clause is needed by the default iter_­move implementation.
— end note]
🔗
constexpr iterator& operator++();
6
#
Effects: Equivalent to: ++value_; return *this;
🔗
constexpr void operator++(int);
7
#
Effects: Equivalent to ++*this.
🔗
constexpr iterator operator++(int) requires incrementable<W>;
8
#
Effects: Equivalent to: auto tmp = *this; ++*this; return tmp;
🔗
constexpr iterator& operator--() requires decrementable<W>;
9
#
Effects: Equivalent to: --value_; return *this;
🔗
constexpr iterator operator--(int) requires decrementable<W>;
10
#
Effects: Equivalent to: auto tmp = *this; --*this; return tmp;
🔗
constexpr iterator& operator+=(difference_type n) requires advanceable<W>;
11
#
Effects: Equivalent to: if constexpr (is-integer-like<W> && !is-signed-integer-like<W>) { if (n >= difference_type(0)) value_ += static_cast<W>(n); else value_ -= static_cast<W>(-n); } else { value_ += n; } return *this;
🔗
constexpr iterator& operator-=(difference_type n) requires advanceable<W>;
12
#
Effects: Equivalent to: if constexpr (is-integer-like<W> && !is-signed-integer-like<W>) { if (n >= difference_type(0)) value_ -= static_cast<W>(n); else value_ += static_cast<W>(-n); } else { value_ -= n; } return *this;
🔗
constexpr W operator[](difference_type n) const requires advanceable<W>;
13
#
Effects: Equivalent to: return W(value_­ + n);
🔗
friend constexpr bool operator==(const iterator& x, const iterator& y) requires equality_­comparable<W>;
14
#
Effects: Equivalent to: return x.value_­ == y.value_­;
🔗
friend constexpr bool operator<(const iterator& x, const iterator& y) requires totally_­ordered<W>;
15
#
Effects: Equivalent to: return x.value_­ < y.value_­;
🔗
friend constexpr bool operator>(const iterator& x, const iterator& y) requires totally_­ordered<W>;
16
#
Effects: Equivalent to: return y < x;
🔗
friend constexpr bool operator<=(const iterator& x, const iterator& y) requires totally_­ordered<W>;
17
#
Effects: Equivalent to: return !(y < x);
🔗
friend constexpr bool operator>=(const iterator& x, const iterator& y) requires totally_­ordered<W>;
18
#
Effects: Equivalent to: return !(x < y);
🔗
friend constexpr auto operator<=>(const iterator& x, const iterator& y) requires totally_­ordered<W> && three_­way_­comparable<W>;
19
#
Effects: Equivalent to: return x.value_­ <=> y.value_­;
🔗
friend constexpr iterator operator+(iterator i, difference_type n) requires advanceable<W>;
20
#
Effects: Equivalent to: return i += n;
🔗
friend constexpr iterator operator+(difference_type n, iterator i) requires advanceable<W>;
21
#
Effects: Equivalent to: return i + n;
🔗
friend constexpr iterator operator-(iterator i, difference_type n) requires advanceable<W>;
22
#
Effects: Equivalent to: return i -= n;
🔗
friend constexpr difference_type operator-(const iterator& x, const iterator& y) requires advanceable<W>;
23
#
Effects: Equivalent to: using D = difference_type; if constexpr (is-integer-like<W>) { if constexpr (is-signed-integer-like<W>) return D(D(x.value_) - D(y.value_)); else return (y.value_ > x.value_) ? D(-D(y.value_ - x.value_)) : D(x.value_ - y.value_); } else { return x.value_ - y.value_; }