std::basic_string_view<CharT,Traits>:: compare
From cppreference.com
<
cpp
|
string
|
basic string view
|
constexpr
int
compare
(
basic_string_view v
)
const
noexcept
;
|
(1) | (since C++17) |
|
constexpr
int
compare
(
size_type pos1, size_type count1,
basic_string_view v ) const ; |
(2) | (since C++17) |
|
constexpr
int
compare
(
size_type pos1, size_type count1, basic_string_view v,
size_type pos2, size_type count2 ) const ; |
(3) | (since C++17) |
|
constexpr
int
compare
(
const
CharT
*
s
)
const
;
|
(4) | (since C++17) |
|
constexpr
int
compare
(
size_type pos1, size_type count1,
const CharT * s ) const ; |
(5) | (since C++17) |
|
constexpr
int
compare
(
size_type pos1, size_type count1,
const CharT * s, size_type count2 ) const ; |
(6) | (since C++17) |
Compares two character sequences.
1)
The length
rlen
of the sequences to compare is the smaller of
size
(
)
and
v.
size
(
)
. The function compares the two views by calling
traits
::
compare
(
data
(
)
, v.
data
(
)
, rlen
)
, and returns a value according to the following table:
| Condition | Result | Return value | |
|---|---|---|---|
Traits::compare(data(), v.data(),
rlen
) < 0
|
this
is
less
than
v
|
< 0 | |
Traits::compare(data(), v.data(),
rlen
) == 0
|
size() < v.size()
|
this
is
less
than
v
|
< 0 |
size() == v.size()
|
this
is
equal
to
v
|
0 | |
size() > v.size()
|
this
is
greater
than
v
|
> 0 | |
Traits::compare(data(), v.data(),
rlen
) > 0
|
this
is
greater
than
v
|
> 0 | |
2)
Equivalent to
substr
(
pos1, count1
)
.
compare
(
v
)
.
3)
Equivalent to
substr
(
pos1, count1
)
.
compare
(
v.
substr
(
pos2, count2
)
)
.
4)
Equivalent to
compare
(
basic_string_view
(
s
)
)
.
5)
Equivalent to
substr
(
pos1, count1
)
.
compare
(
basic_string_view
(
s
)
)
.
6)
Equivalent to
substr
(
pos1, count1
)
.
compare
(
basic_string_view
(
s, count2
)
)
.
Parameters
| v | - | view to compare |
| s | - | pointer to the character string to compare to |
| count1 | - | number of characters of this view to compare |
| pos1 | - | position of the first character in this view to compare |
| count2 | - | number of characters of the given view to compare |
| pos2 | - | position of the first character of the given view to compare |
Return value
Negative value if this view is less than the other character sequence, zero if the both character sequences are equal, positive value if this view is greater than the other character sequence.
Complexity
1) Linear in the number of characters compared.
Example
Run this code
#include <string_view> int main() { using std::operator""sv; static_assert("abc"sv.compare("abcd"sv) < 0); static_assert("abcd"sv.compare("abc"sv) > 0); static_assert("abc"sv.compare("abc"sv) == 0); static_assert(""sv.compare(""sv) == 0); }
See also
|
compares two strings
(public member function of
std::basic_string<CharT,Traits,Allocator>
)
|
|
|
(C++17)
(removed in C++20)
(removed in C++20)
(removed in C++20)
(removed in C++20)
(removed in C++20)
(C++20)
|
lexicographically compares two string views
(function template) |