问一个关于模板的问题
为了保存一份不相同的字符串表，我们可以使用以下数据结构（在实际的情况中，它并非最优案）：
std::set<std::wstring> MyStringTable;
如果现在的需求是，在比较字符串时不区分大小写，请写出如何修改以上的定义。提示，set类的模版参数为：
template<class _Key, class _Pr = less<_Key>, class _Al = allocator<_Key> >
class set;


[解决办法]

C/C++ code

#include <iostream>#include <set>#include <string>using namespace std;template<class CH=char>struct NocaseCompare{    typedef basic_string<CH> Str;    typedef typename Str::const_iterator IT;    bool operator()(const Str& ls, const Str& rs)    {       IT pl=ls.begin();       IT pr =rs.begin();       while(pl!=ls.end() && pr!=rs.end() && toupper(*pl) ==toupper(*pr))       {           ++pl;           ++pr;       }       if(pl==ls.end())return pl!=rs.end();       if(pr!=rs.end())return false;       return toupper(*pl) <toupper(*pr);    }};void main(){  set<wstring, NocaseCompare<wchar_t> > sets;  set<string, NocaseCompare<char> > csets;}
[解决办法]
C/C++ code
#include <iostream>#include <set>#include <string>using namespace std;template<class CH=char>struct NocaseCompare{    typedef basic_string<CH> Str;    typedef typename Str::const_iterator IT;    bool operator()(const Str& ls, const Str& rs)    {       IT pl=ls.begin();       IT pr =rs.begin();       while(pl!=ls.end() && pr!=rs.end() && toupper(*pl) ==toupper(*pr))       {           ++pl;           ++pr;       }       if(pl==ls.end())return pl!=rs.end();       if(pr!=rs.end())return false;       return toupper(*pl) <toupper(*pr);    }};void main(){  set<wstring, NocaseCompare<wchar_t> > sets;  set<string, NocaseCompare<char> > csets;}
[解决办法]
#include <string>
#include <iostream>
#include <stdlib.h>
#include <algorithm>
#include <iterator>
#include <set>
//---------------------------------------
using namespace std;
template <class T>
struct less_str : public binary_function<T, T, bool>
{
   bool operator()(const T& t1, const T& t2)
   {
       T t3 = t1;
       T t4 = t2;
       transform(t1.begin(), t1.end(), t3.begin(), toupper);
       transform(t2.begin(), t2.end(), t4.begin(), toupper);
       if (t3 < t4)
       {
           return true;
       }
       return false;
   }
};
int main(int argc, char* argv[])
{
   string str1 = "sss";
   string str2 = "SSs";
   set<string, less_str<string> > ustr;
   ustr.insert(str2);
   ustr.insert(str1);
   cout << ustr.size() << endl;
   copy(ustr.begin(), ustr.end(), ostream_iterator<string, char>(cout, ","));
   system("pause");
   return 0;
}
//---------------------------------------
[code=C/C++][/code]