c++0x 学习笔记之 range-based for loop wording - c++编程基础

非常简单，就是 for 循环的精简写法

 
         int 
         array[5] = { 1, 2, 3, 4, 5 }; 
        
         for 
         (
         int
         & x : array) 
        
         x *= 2;

对于容器同样可用，比如与 auto 共用时

 
         std::map mm; 
        
         for
         ( auto i : mm ) 
        
         { 
        
         if 
         ( (*i).first.size() < 3 ) 
        
         (*i).second.append(
         "   "
         ); 
        
         }

可用的容器有
>, <deque>, <forward_list>, <list>, <map>, , <regex>, <set>, <string>, , <unordered_map>, <unordered_set>,,<vector>

for ( for-range-declaration : expression ) statement

等效于

   
    
     
      
       
        
         
          1
         
         
          2
         
         
          3
         
         
          4
         
         
          5
         
         
          6
         
         
          7
         
         
          8
         
        
         
          
           { 
          
          
             
           auto && __range = ( expression ); 
          
          
             
           for 
           (auto __begin = begin-expr, __end = end-expr; __begin != __end; ++__begin ) 
          
          
             
           { 
          
          
               
           for
           -range-declaration = *__begin; 
          
          
               
           statement 
          
          
             
           } 
          
          
           }