How do I format numbers for internatinal locales in C++

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C++

Greetings Kind Regards

I am attempting to duplicate in C++ the work shown on Code Project article titled "International Number Formats" link below. My C++ code is shown below and output also. Each line of output is the number 123.56 in my global locale then the language-nation string then the number per the locale. Please note not all outputs are correct as stated at end of each line.

Thank You Kindly

International Number Formats[^]

1234.56 en-US 1,234.56 ok
1234.56 da-DK 1.234,56 ok
1234.56 it-CH 1Æ234.56 expected 1'234.56
1234.56 fi-FI 1á234,56 expected 1 234,56
1234.56 fa-IR 1,234/56 ok
1234.56 kk-KZ 1┬234,56 expected 1 234-56
1234.56 et-EE 1á234,56 expected 1 234.56

#include <iostream>
#include <locale>
#include <sstream>
using namespace std;

char narrow_space = ' ';
char wide_space = L' ';

#define LINE_FUNCSIG cout << __LINE__ << narrow_space << __FUNCSIG__<<endl;

template<typename charType, typename numberType> requires is_arithmetic_v<numberType>
basic_string<charType> formatted_number(numberType _number, const string& _std_name)
{
	basic_ostringstream<charType> _ostream;
	_ostream.imbue(locale(_std_name));
	_ostream << _number;
	cout << _number << narrow_space << _std_name << narrow_space << _ostream.str() << endl;
	return _ostream.str();
}

// https://www.codeproject.com/articles/78175/international-number-formats

int main()
{
	cout << "Hello World !\n" << boolalpha;
	wcout << L"Again Hello World !\n" << boolalpha << endl;

	auto _number = 1234.56;
	formatted_number<char>(_number, "en-US");
	formatted_number<char>(_number, "da-DK");
	formatted_number<char>(_number, "it-CH");
	formatted_number<char>(_number, "fi-FI");
	formatted_number<char>(_number, "fa-IR");
	formatted_number<char>(_number, "kk-KZ");
	formatted_number<char>(_number, "et-EE");

	return 0;
}

What I have tried:

searched web, examined cppreference.com, inquired ChatGBT, examined "Related Entries"