Cyclic removal of container content such as map,vector (C + +)

Cyclic removal of container content such as map,vector (C + +)

Map,vector and other containers can not be deleted by the normal method:

 for (Auto P=list.begin ();p!=list.end ();p + +)   list.erase (p);

A similar way, will be wrong, do not believe you try to debug:)

Here used a ' iterator ' of a self-increment/decrement, to cleverly implement, delete the current ' iterator, ' but have given the current ' iterator ' assignment for its next operation, not deleted, the current ' iterator ' will expire!

Code:

1#include <iostream>2#include <vector>3#include <map>4 using namespacestd;5 6 intMain ()7 {8      Const char * strs[] = {9         "str1",Ten         "str2", One         "STR3", A         "STR4", -         "STR5", -         "STR6", the         "STR7", -         "Str8", -         "STR9", -         "Str10" +     }; -cout <<"Hello world\n"; +  Amap<string,string>list; atvector<string>arr; -      for(inti =9; i>=0; i--) { - List.emplace (Std::make_pair (Strs[i], strs[i])); - Arr.emplace_back (Strs[i]); -     } -Auto pos =list.end (); inpos--; //Get the first place in the countdown  -      while(pos!= list.end () && list.size () >3) toList.erase (pos--); //Key here  +      while(Arr.size () >3) -Arr.erase (--arr.end ()); //Key here  the      for(Auto s:list) { *cout << s.first.data () <<" "<< S.second.data () <<"\ n"; $     }Panax Notoginseng      for(Auto S:arr) { -cout << s.data () <<"\ n"; the     } +     return 0; A}

Output:

Hello Worldstr1 str1str10 str10str2 str2str10str9str8

Cyclic removal of container content such as map,vector (C + +)