strpbrk.c

// Same function as strpbrk() in libc
// Find the first occurrence in source of a character in chars (excluding NUL).
char* find_char(const char* source, const char* chars)
{
	// For better performance, put the source string and chars in the stack;
	// See strpbrk.c in libc, OpenBSD
	const char* s = source;
	while (*s++ != '\0')
	{
		const char *c = chars;
		while (*c++ != '\0')
		{
			if (*s == *c) return (char*)s;
		}
	}
	return NULL;
}
 
int main (int argc, char const *argv[])
{
	char* c = find_char("ABCDEF", "XRCQEF");
	if (c) printf("The result is [%c]n", *c);
	return 0;
}