ichar_traits.h

C语言数值算法程序大全（第二版）,课本文件

//: C03:ichar_traits.h
// From "Thinking in C++, 2nd Edition, Volume 2"
// by Bruce Eckel & Chuck Allison, (c) 2003 MindView, Inc.
// Available at www.BruceEckel.com.
// Creating your own character traits
#ifndef ICHAR_TRAITS_H
#define ICHAR_TRAITS_H
#include <cassert>
#include <cctype>
#include <cmath>
#include <ostream>
#include <string>

using std::toupper;
using std::tolower;
using std::ostream;
using std::string;
using std::char_traits;
using std::allocator;
using std::basic_string;

struct ichar_traits : char_traits<char> {
  // We'll only change character-by-
  // character comparison functions
  static bool eq(char c1st, char c2nd) {
    return toupper(c1st) == toupper(c2nd);
  }
  static bool ne(char c1st, char c2nd) {
    return !eq(c1st, c2nd);
  }
  static bool lt(char c1st, char c2nd) {
    return toupper(c1st) < toupper(c2nd);
  }
  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(tolower(*str1) < tolower(*str2))
        return -1;
      else if(tolower(*str1) > tolower(*str2))
        return 1;
      assert(tolower(*str1) == tolower(*str2));
      str1++; str2++; // Compare the other chars
    }
    return 0;
  }
  static const char* find(const char* s1, 
    size_t n, char c) {
    while(n-- > 0)
      if(toupper(*s1) == toupper(c))
        return s1;
      else
        ++s1;
    return 0;
  }
};

typedef basic_string<char, ichar_traits> istring;

inline ostream& operator<<(ostream& os, const istring& s) {
  return os << string(s.c_str(), s.length());
}
#endif // ICHAR_TRAITS_H  ///:~