重定義less直接比較char字符串

直接上代碼：

using namespace std;
namespace std
{
	template<>
	struct less<const char *>
	{
		bool operator()(const char  * const  __x, const char * const  __y) const { return strcmp(__x, __y) < 0; }
	};
	template<>
	struct equal_to<const char *>
	{
		bool operator()(const char  * const  __x, const char * const  __y) const { return strcmp(__x, __y) == 0; }
	};
}

printf("%d\n", "abc" < "bcd");

再擴展一下：

	template <typename Object, typename Comparator>
	const Object& findMax(const vector<Object> &arr, Comparator isLessThan)
	{
		int maxIndex = 0;
		for (int i=1; i < arr.size(); i++)
		{
			if (isLessThan(arr[maxIndex], arr[i]))
			{
				maxIndex = i;
			}
		}
		return arr[maxIndex];
	}

	template<typename Object>
	const Object & findMax(const vector<Object>& arr)
	{
		return findMax(arr, less<Object>());
	}

	class CCompare
	{
	public:
		bool operator()(const string& lhs, const string& rhs) const
		{
			return stricmp(lhs.c_str(), rhs.c_str()) < 0;
		}
	};

然後就可以這樣用了：

vector<string> arr(3);
arr[0] = "ZEBRA";
arr[1] = "alligator";
arr[2] = "crocodile";
printf("%d\n", findMax(arr, CCompare()));