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  1. #include <iostream>
  2. #include <vector>
  3. #include <string>
  4.  
  5. class Visitor;
  6.  
  7. class Entry {
  8. public:
  9.   virtual ~Entry() {};
  10.   virtual std::string getName() const = 0;
  11.   virtual size_t getSize() = 0;
  12.   virtual size_t accept(Visitor *v) = 0;
  13. };
  14.  
  15. template <class T>
  16. class Iterator {
  17. public:
  18.   virtual ~Iterator() {}
  19.   virtual bool hasNext() = 0;
  20.   virtual T next() = 0;
  21. };
  22.  
  23. template <class T>
  24. class VectorIterator : public Iterator<T> {
  25.   std::vector<T> &v;
  26.   size_t index = 0;
  27. public:
  28.   VectorIterator(std::vector<T> &v) : v(v) {}
  29.   bool hasNext() override {
  30.     if (index < v.size())
  31.       return true;
  32.     else
  33.       return false;
  34.   }
  35.   T next() {
  36.     T retvalue = v[index];
  37.     index++;
  38.     return retvalue;
  39.   }
  40. };
  41.  
  42. class File : public Entry {
  43.   std::string name;
  44.   size_t size;
  45. public:
  46.   File(std::string name, size_t size) : name(name), size(size) {}
  47.   std::string getName() const override { return name; }
  48.   size_t getSize() override { return size; }
  49.   size_t accept(Visitor *v) override;
  50. };
  51.  
  52. class Directory : public Entry {
  53.   std::string name;
  54.   std::vector<Entry *> v;
  55. public:
  56.   Directory(std::string name) : name(name) {}
  57.   ~Directory() {
  58.     for (auto p : v) delete p;
  59.   }
  60.   std::string getName() const override { return name; }
  61.   size_t getSize() override;
  62.   size_t accept(Visitor *v) override;
  63.   void treePrint();
  64.   void add(Entry *entry) { v.push_back(entry); }
  65.   Iterator<Entry *> *iterator() { return new VectorIterator<Entry *>(v); }
  66. };
  67.  
  68. class Visitor {
  69. public:
  70.   virtual ~Visitor() {}
  71.   virtual size_t visit(File *) = 0;
  72.   virtual size_t visit(Directory *) = 0;
  73. };
  74.  
  75. size_t File::accept(Visitor *v) { return v->visit(this); }
  76. size_t Directory::accept(Visitor *v) { return v->visit(this); }
  77.  
  78. class SizeVisitor : public Visitor {
  79. public:
  80.   size_t visit(File * file) { return file->getSize(); }
  81.   size_t visit(Directory *directory) {
  82.     size_t size = 0;
  83.     Iterator<Entry *> *it = directory->iterator();
  84.     while (it->hasNext()) {
  85.       Entry *entry = it->next();
  86.       size += entry->accept(this);
  87.     }
  88.     delete it;
  89.     return size;
  90.   }
  91. };
  92.  
  93. class ListVisitor : public Visitor {
  94.   std::string currentDirectoryName;
  95.   std::string saveDirectoryName;
  96.  
  97. public:
  98.   size_t visit(File *file) {
  99.     std::cout << currentDirectoryName << "/" << file->getName() << "(" << file->getSize() << ")" << std::endl;
  100.     return 0;
  101.   }
  102.   size_t visit(Directory *dir) {
  103.     std::cout << currentDirectoryName << "/" << dir->getName() << "(" << dir->getSize() << ")" << std::endl;
  104.     saveDirectoryName = currentDirectoryName;
  105.     currentDirectoryName +=  "/" + dir->getName();
  106.     Iterator<Entry *> *it = dir->iterator();
  107.     while (it->hasNext()) {
  108.       Entry *entry = it->next();
  109.       entry->accept(this);
  110.     }
  111.     delete it;
  112.     currentDirectoryName = saveDirectoryName;
  113.     return 0;
  114.   }
  115. };
  116.  
  117. size_t Directory::getSize() {
  118.   Visitor *visitor = new SizeVisitor();
  119.   size_t size = this->accept(visitor);
  120.   delete visitor;
  121.   return size;
  122. }
  123. void Directory::treePrint() {
  124.   Visitor *visitor = new ListVisitor();
  125.   this->accept(visitor);
  126.   delete visitor;
  127. }
  128.  
  129. int main() {
  130.   {
  131.     Directory *rootdir = new Directory("root");
  132.     File *file1 = new File("file1.txt", 100);
  133.     File *file2 = new File("file2.txt", 200);  
  134.     rootdir->add(file1);
  135.     rootdir->add(file2);
  136.     rootdir->treePrint();
  137.  
  138.     delete rootdir;
  139.   }
  140. //  xmallocdump();
  141.   return 0;
  142. }
  143.  
  144.  
Success #stdin #stdout 0.01s 5272KB
comments (?)
stdin 
Standard input is empty
stdout 
/root(300)
/root/file1.txt(100)
/root/file2.txt(200)
https://ideone.com/6d43LO
language:
C++14 (clang 8.0)
created:
113 days ago
visibility:
secret

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