24 Strings library [strings]

24.4 String view classes [string.view]

24.4.2 Class template basic_­string_­view [string.view.template]

24.4.2.6 String operations [string.view.ops]

size_type copy(charT* s, size_type n, size_type pos = 0) const;
Let rlen be the smaller of n and size() - pos.
Throws: out_­of_­range if pos > size().
Requires: [s, s + rlen) is a valid range.
Effects: Equivalent to traits​::​copy(s, data() + pos, rlen).
Returns: rlen.
Complexity: .
constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const;
Let rlen be the smaller of n and size() - pos.
Throws: out_­of_­range if pos > size().
Effects: Determines rlen, the effective length of the string to reference.
Returns: basic_­string_­view(data() + pos, rlen).
constexpr int compare(basic_string_view str) const noexcept;
Let rlen be the smaller of size() and str.size().
Effects: Determines rlen, the effective length of the strings to compare.
The function then compares the two strings by calling traits​::​compare(data(), str.data(), rlen).
Complexity: .
Returns: The nonzero result if the result of the comparison is nonzero.
Otherwise, returns a value as indicated in Table 66.
Table 66compare() results
Condition
Return Value
size() < str.size()
< 0
size() == str.size()
 0
size() > str.size()
> 0
constexpr int compare(size_type pos1, size_type n1, basic_string_view str) const;
Effects: Equivalent to: return substr(pos1, n1).compare(str);
constexpr int compare(size_type pos1, size_type n1, basic_string_view str, size_type pos2, size_type n2) const;
Effects: Equivalent to: return substr(pos1, n1).compare(str.substr(pos2, n2));
constexpr int compare(const charT* s) const;
Effects: Equivalent to: return compare(basic_­string_­view(s));
constexpr int compare(size_type pos1, size_type n1, const charT* s) const;
Effects: Equivalent to: return substr(pos1, n1).compare(basic_­string_­view(s));
constexpr int compare(size_type pos1, size_type n1, const charT* s, size_type n2) const;
Effects: Equivalent to: return substr(pos1, n1).compare(basic_­string_­view(s, n2));