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  1. #include <iostream>
  2. #include <initializer_list>
  3.  
  4. struct list
  5. {
  6.     list() { std::cout << "default constructor\n" ; }
  7.  
  8.     list( std::initializer_list<int> il )
  9.     {
  10.         std::cout << "constructor from initializer_list\n" ;
  11.         for( int v : il ) push_back(v) ;
  12.     }
  13.  
  14.     list( const list& that )
  15.     {
  16.         std::cout << "copy constructor\n" ;
  17.         for( node* n = that.first ; n ; n = n->next ) push_back( n->value ) ;
  18.     }
  19.  
  20.     list( list&& that ) noexcept
  21.     {
  22.         std::cout << "move constructor\n" ;
  23.         first = that.first ; that.first = nullptr ;
  24.         last = that.last ; that.last = nullptr ;
  25.     }
  26.  
  27.     ~list()
  28.     {
  29.         std::cout << "destructor\n" ;
  30.         while(first) pop_back() ;
  31.     }
  32.  
  33.     list& operator=( const list& that ) ; // TODO
  34.     list& operator=( list&& that ) noexcept ; // TODO
  35.  
  36.     void push_back( int v )
  37.     {
  38.         if(last) { last->next = new node( v, last ) ; last = last->next ; }
  39.         else first = last = new node(v) ;
  40.     }
  41.  
  42.     void pop_back()
  43.     {
  44.         if( last != first ) { last = last->prev ; delete last->next ; last->next = nullptr ; }
  45.         if( last && last == first ) { delete last ; last = first = nullptr ; }
  46.     }
  47.  
  48.     struct node
  49.     {
  50.         node( int v ) : value(v) {}
  51.         node( int v, node* p ) : value(v), prev(p) {}
  52.  
  53.         int value ;
  54.         node* next = nullptr ;
  55.         node* prev = nullptr ;
  56.     };
  57.  
  58.     node* first = nullptr ;
  59.     node* last = nullptr ;
  60. };
  61.  
  62. list foo()
  63. {
  64.     std::cout << "in function foo\n" ;
  65.     return { 1, 2, 3, 4, 5 } ;
  66. }
  67.  
  68. list bar()
  69. {
  70.     std::cout << "in function bar\n" ;
  71.     list temp ;
  72.     for( int i = 1 ; i < 6 ; ++i ) temp.push_back(i) ;
  73.     return temp ;
  74. }
  75.  
  76. int main()
  77. {
  78.     {
  79.         list a = foo() ;
  80.         std::cout << "back in main\n" ;
  81.         for( auto n = a.first ; n ; n = n->next ) std::cout << n->value << ' ' ;
  82.         std::cout << '\n' ;
  83.     }
  84.  
  85.     std::cout << "----------------------------\n" ;
  86.  
  87.     {
  88.         list b = bar() ;
  89.         std::cout << "back in main\n" ;
  90.         for( auto n = b.first ; n ; n = n->next ) std::cout << n->value << ' ' ;
  91.         std::cout << '\n' ;
  92.     }
  93. }
  94.  
Success #stdin #stdout 0s 3472KB
comments (?)
stdin
copy 
Standard input is empty
stdout
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in function foo
constructor from initializer_list
back in main
1 2 3 4 5 
destructor
----------------------------
in function bar
default constructor
back in main
1 2 3 4 5 
destructor
https://ideone.com/kK3cIf
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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