str.h

这是本人精心搜集的关于常用图论算法的一套源码

#include<iostream.h>
class String
{
  friend  bool operator==(const String &first, const String &second);
  friend  bool operator>(const String &first, const String &second);
  friend  bool operator<(const String &first, const String &second);
  friend  bool operator>=(const String &first, const String &second);
  friend  bool operator<=(const String &first, const String &second);
  friend  bool operator!=(const String &first, const String &second);	
  friend  ostream &operator<<(ostream&,String &s);
  friend  istream &operator>>(istream&,String &s);
  friend  int strlen(String &s);
  friend  void strcat(String &add_to, const String &add_on);
  friend  void strcpy(String &copy, const String &original);
  friend  void strncpy(String &copy, const String &original, int n);
  friend  void KMP_Fail(const String &pat,int *f);                     // KMP算法中计算模式串pat的失效函数
  friend  int KMP_Find(const String &tag,const String &pat);  // 用KMP算法实现Find  
  friend  int strstr(const String &text, const String &target);
  friend  void write(ostream& out, String &s);


 public: // methods of the string ADT
   String( ){ length=0;  }
   ~String( )
     { if(length>0){ delete[]entries; length=0; } }
   String(const String&); // copy constructor
   String(const char*); // conversion from C-string
   String  operator=(const String &copy); //overloaded assignment operator
   String &operator=(const char*copy);    //overloaded assignment operator
   const char *c_str( ) const; // conversion to C-style string
   int size() { return length; }   
   int Find(const String &pat)const;  // 在字符串中查找模式串pat, 找不到返回-1，否则返回pat在字符串中的位置
 protected:
   char *entries;
   int length;
   void setString(const char *copy);  //auxiliary function
};