20 Strings library [strings]

20.3 String classes [string.classes]

20.3.2 Class template basic_­string [basic.string]

20.3.2.7 String operations [string.ops]

20.3.2.7.9 basic_­string​::​compare [string.compare]

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template<class T> int compare(const T& t) const;
1
#
Effects: Creates a variable, sv, as if by basic_­string_­view<charT, traits> sv = t; and then determines the effective length rlen of the strings to compare as the smaller of size() and sv.size().
The function then compares the two strings by calling traits​::​compare(data(), sv.data(), rlen).
2
#
Returns: The nonzero result if the result of the comparison is nonzero.
Otherwise, returns a value as indicated in Table 58.
Table 58 — compare() results
Condition
Return Value
size() <  sv.size()
< 0
size() == sv.size()
 0
size() >  sv.size()
> 0
3
#
Remarks: This function shall not participate in overload resolution unless is_­convertible_­v<const T&, basic_­string_­view<charT, traits>> is true and is_­convertible_­v<const T&, const charT*> is false.
4
#
Throws: Nothing unless the initialization of sv throws an exception.
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template<class T> int compare(size_type pos1, size_type n1, const T& t) const;
5
#
Effects: Equivalent to: 
{
  basic_string_view<charT, traits> sv = t;
  return basic_string_view<charT, traits>(data(), size()).substr(pos1, n1).compare(sv);
}
6
#
Remarks: This function shall not participate in overload resolution unless is_­convertible_­v<const T&, basic_­string_­view<charT, traits>> is true and is_­convertible_­v<const T&, const charT*> is false.
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template<class T> int compare(size_type pos1, size_type n1, const T& t, size_type pos2, size_type n2 = npos) const;
7
#
Effects: Equivalent to: 
basic_string_view<charT, traits> sv = t;
return basic_string_view<charT, traits>(
    data(), size()).substr(pos1, n1).compare(sv.substr(pos2, n2));
8
#
Remarks: This function shall not participate in overload resolution unless is_­convertible_­v<const T&, basic_­string_­view<charT, traits>> is true and is_­convertible_­v<const T&, const charT*> is false.
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int compare(const basic_string& str) const noexcept;
9
#
Effects: Equivalent to: return compare(basic_­string_­view<charT, traits>(str));
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int compare(size_type pos1, size_type n1, const basic_string& str) const;
10
#
Effects: Equivalent to: return compare(pos1, n1, basic_­string_­view<charT, traits>(str));
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int compare(size_type pos1, size_type n1, const basic_string& str, size_type pos2, size_type n2 = npos) const;
11
#
Effects: Equivalent to: 
return compare(pos1, n1, basic_string_view<charT, traits>(str), pos2, n2);
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int compare(const charT* s) const;
12
#
Returns: compare(basic_­string(s)).
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int compare(size_type pos, size_type n1, const charT* s) const;
13
#
Returns: basic_­string(*this, pos, n1).compare(basic_­string(s)).
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int compare(size_type pos, size_type n1, const charT* s, size_type n2) const;
14
#
Returns: basic_­string(*this, pos, n1).compare(basic_­string(s, n2)).