is contain hangul?

is-contain-hangul.c

#include <stdio.h>
#include <wchar.h>	//wcslen

int is_contain_hangul(const wchar_t *str) {
	const size_t len = wcslen(str);
	const wchar_t start_ch = L'가';
	const wchar_t end_ch = L'힣';
	register int i;

	for (i = 0; i < len; ++i) {
		if (str[i] >= start_ch && str[i] <= end_ch)
			return 1;
	}
	return 0;
}

int main() {
	wchar_t *test_str1 = L"가나다라마";
	wchar_t *test_str2 = L"abcde";
	printf("%d\n", is_contain_hangul(test_str1));
	printf("%d\n", is_contain_hangul(test_str2));

	return 0;
}