fork download 
  1. #include <bits/stdc++.h>
  2.  
  3. using namespace std;
  4.  
  5. struct ChangeNode 
  6. {
  7.     string text;
  8.     ChangeNode* next;
  9.     ChangeNode* pre;
  10.     ChangeNode(string t)
  11.     {
  12.         text = t;
  13.         next = nullptr;
  14.         pre = nullptr;
  15.     }
  16. };
  17.  
  18. class editor 
  19. {
  20. private:
  21.     ChangeNode* current;
  22.  
  23. public:
  24.     //Khoi tao
  25.     editor() : current(new ChangeNode("")) {}
  26.  
  27.     void type(const string &newText) 
  28.     {
  29.         ChangeNode* newNode = new ChangeNode(newText);
  30.         newNode->pre = current;
  31.         current->next = newNode;
  32.         current = newNode;
  33.         cout << "Typed: " << newText << ". Current text: " << getText() << endl;
  34.     }
  35.  
  36.     string undo() 
  37.     {
  38.         if (current != nullptr && current->pre != nullptr) {
  39.             current = current->pre;
  40.             cout << "Undo. Current text: " << getText() << endl;
  41.             return current->text;
  42.         } else {
  43.             cout << "Cannot undo further." << endl;
  44.             return getText();
  45.         }
  46.     }
  47.  
  48.     string redo() 
  49.     {
  50.         if (current != nullptr && current->next != nullptr) 
  51.         {
  52.             current = current->next;
  53.             cout << "Redo. Current text: " << getText() << endl;
  54.             return current->text;
  55.         } 
  56.         else 
  57.         {
  58.             cout << "Cannot redo further." << endl;
  59.             return getText();
  60.         }
  61.     }
  62.  
  63.     string getText() const
  64.     {
  65.         return current->text;
  66.     }
  67.  
  68.     ~editor() 
  69.     {
  70.         ChangeNode* temp;
  71.         while (current != nullptr && current->pre != nullptr) 
  72.         {
  73.             current = current->pre;
  74.         }
  75.         while (current != nullptr) 
  76.         {
  77.             temp = current;
  78.             current = current->next;
  79.             delete temp;
  80.         }
  81.     }
  82. };
  83.  
  84. int main() 
  85. {
  86.     editor e;
  87.     e.type("Hello");
  88.     e.type(" ");
  89.     e.type("World");
  90.  
  91.     e.undo();
  92.     e.undo();
  93.     e.redo();
  94.  
  95.     cout << "Final text: " << e.getText() << endl;
  96.  
  97.     return 0;
  98. }
Success #stdin #stdout 0.01s 5292KB
comments (?)
stdin 
Standard input is empty
stdout 
Typed: Hello. Current text: Hello
Typed:  . Current text:  
Typed: World. Current text: World
Undo. Current text:  
Undo. Current text: Hello
Redo. Current text:  
Final text:
https://ideone.com/gNmvyH
language:
C++14 (gcc 8.3)
created:
3 days ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!