24 Strings library [strings]

24.3 String classes [string.classes]

24.3.2 Class template basic_­string [basic.string]

24.3.2.5 basic_­string element access [string.access]

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const_reference operator[](size_type pos) const; reference operator[](size_type pos);
1
#
Requires: pos <= size().
2
#
Returns: *(begin() + pos) if pos < size().
Otherwise, returns a reference to an object of type charT with value charT(), where modifying the object to any value other than charT() leads to undefined behavior.
3
#
Throws: Nothing.
4
#
Complexity: Constant time.
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const_reference at(size_type pos) const; reference at(size_type pos);
5
#
Throws: out_­of_­range if pos >= size().
6
#
Returns: operator[](pos).
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const charT& front() const; charT& front();
7
#
Requires: !empty().
8
#
Effects: Equivalent to: return operator[](0);
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const charT& back() const; charT& back();
9
#
Requires: !empty().
10
#
Effects: Equivalent to: return operator[](size() - 1);