fork download 
  1. #include <iostream>
  2. using namespace std;
  3.  
  4. class Tracer {
  5. 	static int nextid;
  6. 	int id; 
  7. public:  
  8.     Tracer () : id(++nextid) {
  9.         cout<<"Tracer "<<id<<" created"<<endl;     	
  10.     }
  11.     ~Tracer() {
  12.          cout<<"Tracer "<<id<<" destroyed"<<endl;     	
  13.     }
  14. };
  15. int Tracer::nextid =0; 
  16.  
  17. int main()
  18. {
  19. 	{
  20.     	struct Simple { Tracer i; } s;
  21.     	s.i.~Tracer();           // not needed if integer. 
  22.     	new (&s.i) Tracer;       // the lifecyle of the newly created object 
  23.         	                     // will auto, since Simple will be destroyed when
  24.             	                 // going out of scope
  25. 	}
  26. 	cout << "Simple went out of scope"<<endl;
  27.  
  28. 	{
  29.     	struct Complex { char s[256]; } c; 
  30.     	Tracer *p = new (&c.s) Tracer;  // the lifecycle of the newly created object 
  31.                             // is dynamic.  You'll need to delete it in time. 
  32.                             // because compiler doesn't know about its true nature
  33.                             // and memory will be lost when going out of scope
  34.         p->~Tracer(); 
  35.     }
  36. 	cout << "Complex went out of scope"<<endl;
  37. }
Success #stdin #stdout 0s 15240KB
comments (?)
stdin 
Standard input is empty
stdout 
Tracer 1 created
Tracer 1 destroyed
Tracer 2 created
Tracer 2 destroyed
Simple went out of scope
Tracer 3 created
Tracer 3 destroyed
Complex went out of scope
https://ideone.com/2DMZdQ
language:
C++14 (gcc 8.3)
created:
5 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!