fork(1) download
copy 
  1. #include <iostream>
  2. #include <memory>
  3.  
  4. int treasury = 1000000;
  5.  
  6. class Investment {
  7. 	int value_;
  8.   public:
  9.     static const int MINIMUM = 25;
  10.  
  11.     Investment() : value_(0) {}
  12.     virtual ~Investment() { }
  13.     void buy(int amount) { value_ += amount; }
  14.  
  15.     static void seize(Investment *inv){
  16.     	if(inv)
  17.     	  treasury += inv->value_;
  18.     	delete inv;
  19.     }
  20. };
  21.  
  22. class Bond : public Investment  {
  23. };
  24.  
  25. class Stock : public Investment {
  26. };
  27.  
  28. std::shared_ptr<Investment> createInvestment(bool buy_stock) {
  29.   // Why bother with the deleter here:
  30.   //std::shared_ptr<Investment> inv(nullptr, Investment::seize);
  31.  
  32.   // this works just as well:
  33.   std::shared_ptr<Investment> inv;
  34.  
  35.   if (buy_stock) {
  36.     //inv = std::shared_ptr<Investment>(new Stock(), Investment::seize);
  37.     inv.reset(new Stock(), Investment::seize);
  38.     //inv.reset(new Stock()); // This seems to remove the existing deleter
  39.   } else {
  40.   	inv.reset(new Bond(), Investment::seize);
  41.   }
  42.  
  43.   inv->buy(Investment::MINIMUM);
  44.  
  45.   return inv;
  46. }
  47.  
  48. void playTheMarkets() {
  49.   std::shared_ptr<Investment> stocks(createInvestment(true)); 
  50.   std::shared_ptr<Investment> bonds(createInvestment(false));	
  51. }
  52.  
  53. int main() {
  54.   playTheMarkets();
  55.   std::cout << treasury << std::endl;
  56. }
Success #stdin #stdout 0s 3432KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
1000050
https://ideone.com/BUjOwZ
Experiment with Scott Meyers's Effective Cpp, item 18
language:
C++14 (gcc 8.3)
created:
10 years 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!