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  1. #include <iostream>
  2. #include <string>
  3.  
  4. class Book {
  5. private:
  6.   std::string name;
  7. public:
  8.   Book(){};
  9.   Book(std::string name);
  10.   ~Book(){};
  11.   std::string getName();
  12.   friend std::ostream &operator<<(std::ostream &s, Book *b);
  13. };
  14.  
  15. class BookShelfIterator;
  16.  
  17. class BookShelf {
  18. private:
  19.   Book **books;
  20.   int maxsize;
  21.   int last;
  22. public:
  23.   BookShelf(int maxsize);
  24.   ~BookShelf();
  25.   Book *getBookAt(int index);
  26.   void appendBook(Book *book);
  27.   int getLength();
  28.   BookShelfIterator *iterator();
  29. };
  30.  
  31. class BookShelfIterator {
  32. private:
  33.   BookShelf *bookShelf;
  34.   int index;
  35. public:
  36.   BookShelfIterator(BookShelf *bookShelf);
  37.   ~BookShelfIterator(){};
  38.   bool hasNext();
  39.   Book *next();
  40. };
  41. /*-----------------------------------------------*/
  42.  
  43. Book::Book(std::string name) { this->name = name; }
  44. std::string Book::getName() {return this->name; }
  45. std::ostream &operator<<(std::ostream &s, Book *b) {
  46.   s << b->name;
  47.   return s;
  48. }
  49. /*-----------------------------------------------*/
  50. BookShelf::BookShelf(int maxsize) {
  51.   this->books = new Book* [maxsize];
  52.   this->maxsize = maxsize;
  53.   this->last = 0;
  54. }
  55. BookShelf::~BookShelf() { delete [] (this->books); }
  56. Book *BookShelf::getBookAt(int index) { return this->books[index]; }
  57. void BookShelf::appendBook(Book *book) {
  58.   if (last < maxsize) {
  59.     this->books[last] = book;
  60.     this->last++;
  61.   }
  62. }
  63. int BookShelf::getLength() { return this->last; }
  64.  
  65. BookShelfIterator *BookShelf::iterator() { return new BookShelfIterator(this); }
  66.  
  67. /*-----------------------------------------------*/
  68. BookShelfIterator::BookShelfIterator(BookShelf *bookShelf) {
  69.   this->bookShelf = bookShelf;
  70.   this->index = 0;
  71. }
  72. bool BookShelfIterator::hasNext() {
  73.   if (this->index < bookShelf->getLength()) return true;
  74.   else return false;
  75. }
  76. Book *BookShelfIterator::next() {
  77.   Book *book = bookShelf->getBookAt(index);
  78.   index++;
  79.   return book;
  80. }
  81.  
  82. template<class T, class U>
  83. void shelf_for_each(T& shelf, U func) {
  84.   auto it = shelf->iterator();
  85.   while (it->hasNext()) {
  86. 	func(it->next());
  87.   }
  88.   delete it;
  89. }
  90.  
  91. int main() {
  92.   BookShelf *bookShelf = new BookShelf(4);
  93.   bookShelf->appendBook(new Book("A"));
  94.   bookShelf->appendBook(new Book("BB"));
  95.   bookShelf->appendBook(new Book("CCC"));
  96.   bookShelf->appendBook(new Book("DDDD"));
  97.   shelf_for_each(bookShelf, [](Book* book){std::cout << book << std::endl;});
  98.   delete bookShelf;
  99.   return 0;
  100. }
  101.  
Success #stdin #stdout 0s 16056KB
comments (?)
stdin 
Standard input is empty
stdout 
A
BB
CCC
DDDD
https://ideone.com/sFzBq4
language:
C++ (gcc 8.3)
created:
8 years ago
visibility:
public

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