Delete the STD: Map element in the C ++ traversal.

It is very easy to delete an element in STD: List. Use the erase method directly,CodeAs follows:

 For  ( ITER    =    List. Begin  ( )  ;    ITER    !  =    List. End  (  ) ;  )     { 
 If     ( Shoulddelete (  * ITER)  ) 
ITER    =    List. Erase  ( ITER )  ; 
Else 
 ++ ITER ; 
 } 

Or simpler.

List. Erase  ( STD::  Remove_if  ( List. Begin  (  ) , List. End  ( ) , Shoulddelete ) , List_end (  )  )  ; 

However, according to the definition of void erase (iterator POS) in stl std: map, this erase does not return the iterator of the next element. Therefore, the STD: list method cannot be used.

The truth is that 'erase' in Associative containers doesn' t invalidate any iterators should t those that point to elements being erased (That's also true for 'sid: list '). for this reason, you don't really need 'map: erase 'to return an iterator. just do this

 For  ( ITER    =    Map.Begin  (  )  ;    ITER    !  =    Map. End (  )  ;  )     { 
 If     ( Shoulddelete(  * ITER )  ) 
Map. Erase  ( ITER ++  ) ; 
 Else 
 ++ ITER ; 
 } 

Of course, this method is also suitable for STD: List and so on.