Debug Assertion Failed when using ispunct('ø') - c++

Question

I am writing a program that handles large portions of text, and need to remove punctuation. I encountered a Debug Assertion Failed error, and isolated it to this: It occurs when testing ispunct() on non-English letters.
my test-program is now like this:
main.c
int main() {
ispunct('ø');
cin.get();
return 0;
}
The Debug Assertion Failed window looks like this:
Screenshot of the error
All non-English letters I have tried cause this problem, including 'æ', 'ø', 'å', 'é', etc. Punctuation and English letters do not cause the problem. It's probably something very simple that I am overlooking, so I am thankful for any help!

Answer 1

Character 'ø' must be representable as an unsigned char, otherwise you should use type wchar_t and std::ispunct, for example:
#include <iostream>
#include <locale>
int main()
{
const wchar_t c = L'ø';
std::locale loc("en_US.UTF-8");
std::ispunct(c, loc);
}
For your problem, you can also do this:
#include <locale>
#include <string>
#include <algorithm>
#include <functional>
int main()
{
std::wstring word = L"søme.?.thing";
std::locale loc("en_US.UTF-8");
using namespace std::placeholders;
word.erase(std::remove_if(word.begin(), word.end(),
std::bind(std::ispunct<wchar_t>, _1, loc)), word.end());
std::wcout << word << std::endl;
}