大小忽略的字符串比较

大小忽略的字符串比较

#include  < cassert >
#include  < cctype >
#include  < cmath >
#include  < cstddef >
#include  < ostream >
#include  < string >
using  std::allocator;
using  std::basic_string;
using  std:: string ;
using  std::char_traits;
using  std::ostream;
using  std::tolower;
using  std::tolower;
class  ichar_traints: public  char_traits < char >
{
public :
    static   int  compare( const   char   * str1, const   char   * str2,size_t n)
    {
        for (size_t i = 0 ; i < n; i ++ )
        {
            if (str1 == 0 )
                return   - 1 ;
            else   if (str2 == 0 )
                return   1 ;
            else   if (toupper( * str1) < toupper( * str2))
                return   - 1 ;
            else   if (toupper( * str1) > toupper( * str2))
                return   1 ;
           assert(tolower( * str1) == tolower( * str2));
           str1 ++ ;
           str2 ++ ;

       }
        return   0 ;
   }
} ;
typedef basic_string < char ,ichar_traints >  istring;
inline ostream &   operator << (ostream  & os,istring &  str)
{
    os << string (str.c_str());
}
int  _tmain( int  argc, _TCHAR *  argv[])
{
      //建立二个字符大小写不同的串
    istring s1 = " qianweifeng " ;
    istring s2 = " QianweiFeng " ;
    std::cout << s1.compare(s2);
     int  pause;
    std::cin >> pause;
     return   0 ;
}

摘自Thinking in C++