27 Strings library [strings]

27.3 String view classes [string.view]

27.3.3 Class template basic_string_view [string.view.template]

27.3.3.8 String operations [string.view.ops]

constexpr size_type copy(charT* s, size_type n, size_type pos = 0) const;
Let rlen be the smaller of n and size() - pos.
Preconditions: [s, s + rlen) is a valid range.
Effects: Equivalent to traits​::​copy(s, data() + pos, rlen).
Returns: rlen.
Throws: out_of_range if pos > size().
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.
Effects: Determines rlen, the effective length of the string to reference.
Returns: basic_string_view(data() + pos, rlen).
Throws: out_of_range if pos > size().
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).
Returns: The nonzero result if the result of the comparison is nonzero.
Otherwise, returns a value as indicated in Table 83.
Table 83: compare() results [tab:string.view.compare]
Condition
Return Value
size() < str.size()
< 0
size() == str.size()
 0
size() > str.size()
> 0
Complexity: .
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));
constexpr bool starts_with(basic_string_view x) const noexcept;
Let rlen be the smaller of size() and x.size().
Effects: Equivalent to: return basic_string_view(data(), rlen) == x;
constexpr bool starts_with(charT x) const noexcept;
Effects: Equivalent to: return !empty() && traits​::​eq(front(), x);
constexpr bool starts_with(const charT* x) const;
Effects: Equivalent to: return starts_with(basic_string_view(x));
constexpr bool ends_with(basic_string_view x) const noexcept;
Let rlen be the smaller of size() and x.size().
Effects: Equivalent to: return basic_string_view(data() + (size() - rlen), rlen) == x;
constexpr bool ends_with(charT x) const noexcept;
Effects: Equivalent to: return !empty() && traits​::​eq(back(), x);
constexpr bool ends_with(const charT* x) const;
Effects: Equivalent to: return ends_with(basic_string_view(x));
constexpr bool contains(basic_string_view x) const noexcept; constexpr bool contains(charT x) const noexcept; constexpr bool contains(const charT* x) const;
Effects: Equivalent to: return find(x) != npos;