std::basic_string<CharT,Traits,Allocator>::size,std::basic_string<CharT,Traits,Allocator>::length (3) - Linux Manuals
std::basic_string<CharT,Traits,Allocator>::size,std::basic_string<CharT,Traits,Allocator>::length: std::basic_string<CharT,Traits,Allocator>::size,std::basic_string<CharT,Traits,Allocator>::length
Command to display std::basic_string<CharT,Traits,Allocator>::size,std::basic_string<CharT,Traits,Allocator>::length
manual in Linux: $ man 3 std::basic_string<CharT,Traits,Allocator>::size,std::basic_string<CharT,Traits,Allocator>::length
NAME
std::basic_string<CharT,Traits,Allocator>::size,std::basic_string<CharT,Traits,Allocator>::length - std::basic_string<CharT,Traits,Allocator>::size,std::basic_string<CharT,Traits,Allocator>::length
Synopsis
size_type size() const; (until C++11)
size_type size() const noexcept; (since C++11)
size_type length() const; (until C++11)
size_type length() const noexcept; (since C++11)
Returns the number of CharT elements in the string, i.e. std::distance(begin(), end()).
Parameters
(none)
Return value
The number of CharT elements in the string.
Complexity
Unspecified (until C++11)
Constant (since C++11)
Notes
For std::string, the elements are bytes (objects of type char), which are not the same as characters if a multibyte encoding such as UTF-8 is used.
Example
// Run this code
#include <cassert>
#include <iterator>
#include <string>
int main()
{
std::string s("Exemplar");
assert(8 == s.size());
assert(s.size() == s.length());
assert(s.size() == static_cast<std::string::size_type>(
std::distance(s.begin(), s.end())));
std::u32string a(U"ハロー・ワールド"); // 8 code points
assert(8 == a.size()); // 8 code units in UTF-32
std::u16string b(u"ハロー・ワールド"); // 8 code points
assert(8 == b.size()); // 8 code units in UTF-16
std::string c(u8"ハロー・ワールド"); // 8 code points
assert(24 == c.size()); // 24 code units in UTF-8
}
See also
checks whether the string is empty
empty (public member function)
returns the maximum number of characters
max_size (public member function)
Pages related to std::basic_string<CharT,Traits,Allocator>::size,std::basic_string<CharT,Traits,Allocator>::length
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