21 Strings library [strings]

21.4 String view classes [string.view]

21.4.2 Class template basic_­string_­view [string.view.template]

21.4.2.4 Element access [string.view.access]

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constexpr const_reference operator[](size_type pos) const;
1
#
Preconditions: pos < size().
2
#
Returns: data_­[pos].
3
#
Throws: Nothing.
4
#
[ Note
:
Unlike basic_­string​::​operator[], basic_­string_­view​::​operator[](size()) has undefined behavior instead of returning charT().
— end note
 ]
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constexpr const_reference at(size_type pos) const;
5
#
Throws: out_­of_­range if pos >= size().
6
#
Returns: data_­[pos].
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constexpr const_reference front() const;
7
#
Preconditions: !empty().
8
#
Returns: data_­[0].
9
#
Throws: Nothing.
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constexpr const_reference back() const;
10
#
Preconditions: !empty().
11
#
Returns: data_­[size() - 1].
12
#
Throws: Nothing.
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constexpr const_pointer data() const noexcept;
13
#
Returns: data_­.
14
#
[ Note
:
Unlike basic_­string​::​data() and string-literals, data() may return a pointer to a buffer that is not null-terminated.
Therefore it is typically a mistake to pass data() to a function that takes just a const charT* and expects a null-terminated string.
— end note
 ]