Idiom #169 String length

Assign to the integer n the number of characters of the string s.
Make sure that multibyte characters are properly handled.
n can be different from the number of bytes of s.

auto utf8len(std::string_view const& s) -> size_t
{
	std::setlocale(LC_ALL, "en_US.utf8");

	auto n = size_t{};
	auto size = size_t{};
	auto mb = std::mbstate_t{};

	while(size < s.length())
	{
		size += mbrlen(s.data() + size, s.length() - size, &mb);
		n += 1;
	}

	return n;
}

Demo

n : Integer := s'Length;

(defn n[s] (.codePointCount s 0 (count s)))

Demo

(def n (.codePointCount s 0 (count s)))

Demo

IDENTIFICATION DIVISION.
PROGRAM-ID. length.
PROCEDURE DIVISION.
   MOVE FUNCTION LENGTH(s) TO n
STOP RUN.

int n = s.Length;

Demo
Doc

std.range;

size_t n = s.walkLength;

size_t n = s.length;

import std.uni, std.range;

size_t n = s.byGrapheme.walkLength;

int n = s.length;

Demo
Doc

n = String.length s

Demo
Doc

N = string:length(S)

n = len(s)

import "unicode/utf8"

n := utf8.RuneCountInString(s)

Demo
Doc

n = length s

const n = s.length;

const n = [...s].length;

int n = s.length();

val n = s.length

Demo
Doc

(setf n (length s))

(length s)

local utf8={}
function utf8.bytes(str,index)
 local byte=string.byte(str,index)
 local ret
 if     byte==nil then ret=0
 elseif byte<128  then ret=1
 elseif byte<192  then ret=2
 elseif byte<224  then ret=3
 else                  ret=4
 end
 return ret
end
function utf8.len(str)
 local count=0
 local fini=#str+1
 local index=1
 while index~=fini do
  count=count+1
  index=index+utf8.bytes(str,index)
 end
 return count
end
local n=utf8.len(s)