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  1. #include <bits/stdc++.h>
  2.  
  3. using namespace std;
  4.  
  5. struct Node {
  6.     string url;
  7.     Node* pre;
  8.     Node(string u) 
  9.     {
  10.         url = u;
  11.         pre = nullptr;
  12.     }
  13. };
  14.  
  15. class BrowserHis 
  16. {
  17. private:
  18.     Node* current;
  19.  
  20. public:
  21.     BrowserHis(){ 
  22.         current = nullptr;
  23.     }
  24.  
  25.     void visit(const string& url) 
  26.     {
  27.         Node* newPage = new Node(url);
  28.         newPage->pre = current;
  29.         current = newPage;
  30.         cout << "Visited: " << url << endl;
  31.     }
  32.  
  33.     string back() {
  34.         if (current != nullptr && current->pre != nullptr) 
  35.         {
  36.             current = current->pre;
  37.             cout << "Going back to: " << current->url << endl;
  38.             return current->url;
  39.         } 
  40.         else 
  41.         {
  42.             cout << "Cannot go back further." << endl;
  43.             return "";
  44.         }
  45.     }
  46.  
  47.     string getCurrentPage() const 
  48.     {
  49.         if (current != nullptr) return current->url;
  50.         else return "No history.";
  51.     }
  52.  
  53.     // Giai phong bo nho
  54.     ~BrowserHis() {
  55.         Node* tmp;
  56.         while (current != nullptr) 
  57.         {
  58.             tmp = current;
  59.             current = current->pre;
  60.             delete tmp;
  61.         }
  62.     }
  63. };
  64.  
  65. int main() {
  66.     BrowserHis his;
  67.     his.visit("google.com");
  68.     his.visit("facebook.com");
  69.     his.visit("youtube.com");
  70.  
  71.     cout << "Current page: " << his.getCurrentPage() << endl;
  72.  
  73.     his.back();
  74.     cout << "Current page: " << his.getCurrentPage() << endl;
  75.  
  76.     his.back();
  77.     cout << "Current page: " << his.getCurrentPage() << endl;
  78.  
  79.     his.back();
  80.  
  81.     return 0;
  82. }
Success #stdin #stdout 0.01s 5288KB
comments (?)
stdin 
Standard input is empty
stdout 
Visited: google.com
Visited: facebook.com
Visited: youtube.com
Current page: youtube.com
Going back to: facebook.com
Current page: facebook.com
Going back to: google.com
Current page: google.com
Cannot go back further.
https://ideone.com/ybR6Ve
language:
C++14 (gcc 8.3)
created:
3 days ago
visibility:
public

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