C function strcmp achieve

int strcmp(const char* src, const char* dst)
{
	int ret = 0;
	while (!(ret = *src - *dst) && *dst)
	{
		++src;
		++dst;
	}

	if (ret < 0)
		ret = -1;
	else if (ret > 0)
		ret = 1;

	return ret;
}

int main()
{
	char str[10] = "1234567";
	char str1[10] = "12345678";
	char str2[10] = "123456";
	
	cout << strcmp(str, str1) << endl;

	cout << strcmp(str, str2) << endl;

	cout << strcmp(str, str) << endl;

	system("pause");
	return 0;
}