C / C++ / MFC

template <class InIt, class FwIt>
bool search_input(InIt begin, InIt end, FwIt find1, FwIt find2)
{
	FwIt findstart(find1);
	while (begin != end)
	{
		if (tolower(*begin) == tolower(*find1))
		{
			while (find1 != find2 && begin != end && tolower(*begin) == tolower(*find1))
			{
				++find1;
				++begin;				
			}
			if (find1 == find2)
			{
				return true;
			}
			find1 = findstart;
			continue;
		}
		++begin;
	} 
	return false;
}

bool FindInFile(const char* file, std::string str)
{
	std::ifstream In(file, std::ios::in|std::ios::binary);
	if (!In)
	{
		return false;
	}

	std::string s = str::strlower(std::string(str));

	while (search_input(std::istreambuf_iterator<char>(In), 
		   std::istreambuf_iterator<char>(), s.begin(), s.end()))
	{
		return true;
	}

	return false;
}