Queue. h

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 1   Const     Int  Maxqueue  =     50  ;
  2   
  3     Enum  Error_code
  4  {
  5   Success, overflow, underflow, fail  //  No;  
  6     };
  7   
  8   Template  <  Class  T  > 
  9     Class  Queue
  10   {
  11     Public  :
  12   Queue ();
  13     Bool  Empty () Const  ;
  14   Error_code serve ();
  15   Error_code append (  Const  T  &  ITEM );
  16   Error_code retrieve (T  &  Item)  Const  ;
 17     Protected  :
  18     Int  Count;
  19     Int  Front, rear;
  20   T entry [maxqueue];
  21   };
  22  
  23   Template  <  Class  T  >  
  24   Queue  <  T  >  : Queue ()
  25   {
  26  Count  =     0  ;
  27   Rear  =  Maxqueue  -     1  ;
  28   Front  =     0 ;
  29   }
  30   
  31   Template  <  Class  T  >  
  32     Bool  Queue  <  T >  : Empty ()  Const  
  33   {
  34     Return  Count  =     0  ;
  35   }
  36   
 37   Template  <  Class  T  >  
  38   Error_code queue  <  T  >  : Append (  Const  T  &  Item)
 39   {
  40     If  (Count  > =  Maxqueue)
  41     Return  Overflow;
  42   Count  ++  ;
  43  Rear  =  (Rear  +  1  )  =  Maxqueue)  ?     0  :( Rear  +  1  );
  44   Entry [rear]  = Item;
  45     Return  Success;
  46   }
  47   
  48   Template  <  Class  T  >  
  49  Error_code queue  <  T  >  : Serve ()
  50   {
  51     If  (Count  <=     0  )
  52    Return  Underflow;
  53   Count  --  ;
  54   Front  =  (Front  +  1  )  =  Maxqueue)  ?    0  :( Front  +  1  );
  55     Return  Success;
  56   }
  57   
  58   Template  <  Class  T >  
  59   Error_code queue  <  T  >  : Retrieve (T  &  Item)  Const  
  60   {
  61     If (Count  <=     0  )
  62     Return  Underflow;
  63   Item  =  Entry [Front];
  64     Return  Success;
 65   }