C ++ data structures and algorithms (4) Circular linked list of linear tables

I wrote a two-way linked list in the previous article. Today I reviewed the circular linked list and wrote a circular linked list with a header node. The specific implementation is as follows:

Node file (listnode. h ):

 template 
   
    class  
    circularlist; template  
    
     class  
     listnode { 
     Public  
    : friend  
     class  circularlist 
     
     ; listnode (): m_pnext (null) {} listnode ( 
      const  T data, listnode 
     
       * pnext = 
       null): m_data (data ), m_pnext (pnext) {} ~ 
       listnode () {m_pnext  = 
       NULL ;}  
       private  
      : T m_data; listnode  
      
        * 
        m_pnext ;};  
      
     
    
   
  

Circular linked list file (circularlist. h ):

# Include "  Listnode. h  "  Template <Typename T> Class  Circularlist {  Public  : Circularlist (): Head (  New Listnode <t> () {Head -> M_pnext = Head ;} ~Circularlist () {emptylist (); Delete head ;}  Public  :  Void Emptylist (); //  Clear linked list      Int Length (); //  Calculate the length of a linked list      Bool Insert (T item, Int N = 0 ); //  Insert element Listnode <t> * Find (Int N ); //  Find the nth Element T Delete ( Int N ); //  Delete nth Element T getdata ( Int N ); //  Obtain the nth Element      Void Print (); //  Output linked list  Private  : Listnode <T> *Head ;}; Template <Typename T> Void Circularlist <t> : Emptylist (){  //  Clear linked list Listnode <t> * P = head ,* Pdel;  While (P-> m_pnext! = Head) {pdel = P-> M_pnext; P -> M_pnext = pdel-> M_pnext; Delete pdel;} Template <Typename T> Int Circularlist <t>: Length (){  //  Calculate the length of a linked list      Int Count = 0  ; Listnode <T> * P = Head;  While (P-> m_pnext! = Head) {count ++ ; P = P-> M_pnext ;}  Return  Count;} Template <Typename T>Bool Circularlist <t >:: insert (T item, Int N = 0  ){  //  Insert element      If (N < 0 | N> Length ())  Return   False ; //  N outbound Listnode <t> * P = Head; listnode <T> * pnewnode =New Listnode <t> (Item );  If (Pnewnode = Null)  Return   False  ;  For ( Int I = 0 ; I <n; I ++ ) {P = P-> M_pnext;  If (P = Head) Return   False ; //  N outbound  } Pnewnode -> M_pnext = p-> M_pnext; P -> M_pnext = Pnewnode;  Return   True  ;} Template <Typename T> Listnode <T> * circularlist <t>: Find ( Int  N ){  // Find the nth Element      If (N < 0 | N> Length ())  Return   False  ; Listnode <T> * P = Head;  While (P! = Head) {P = P-> M_pnext ;}  If (P = Head)  Return NULL;  Return  P;} Template <Typename T> T circularlist <T>: delete ( Int  N ){  //  Delete nth Element      If (N < 0 | N> Length ())  Return  NULL; listnode <T> * P = head ,* Pdel; For ( Int I = 0 ; I <n; I ++ ) {P = P-> M_pnext;} pdel = P-> M_pnext; P -> M_pnext = pdel-> M_pnext; t data = Pdel-> M_data; Delete pdel;  Return  Data;} Template <Typename T> T circularlist <T>: getdata ( Int N ){  //  Obtain the nth Element      If (N < 0 | N> Length ())  Return  NULL; listnode <T> * P = Head;  For ( Int I = 0 ; I <n; I ++ ) {P = P-> M_pnext ;} Return  P;} Template <Typename T> Void Circularlist <t> : Print () {listnode <T> * P = Head; cout < "  Head  "  ;  While (P-> m_pnext! = Head) {P = P-> M_pnext; cout < " -->  " <P-> M_data;} cout < "  -->  " < Endl ;} 

Test file (circularlist. h ):

 //  Circularlist. cpp: defines console applications.Program.  //  # Include  "  Stdafx. h "  # Include  "  Circularlist. h  "  # Include <Iostream> Using   Namespace  STD;  Int _ Tmain ( Int Argc, _ tchar * Argv []) {circularlist < Int > Circularlist;  For ( Int I = 0 ; I < 15 ; I ++ ) Circularlist. insert (I * 3  , I); circularlist. Print (); cout < "  The length of list is:  " <Circularlist. Length () < Endl;  Int Del = circularlist. Delete ( 3 ); Cout <Del < "  Is deleted  " < Endl; circularlist. Print (); cout < "  The length of list is:  " <Circularlist. Length () < Endl; cin.  Get  ();  Return   0  ;} 

Test: