Shows how modern C++ can use RAII helper objects to provide the "defer" feature just introduced in Swift 2.0

demoDefer.cpp

// shows how C++11 can implement the "defer" introduced in Swift 2.0
#include <iostream>

using simpleClosure = std::function<void()>;  // new typedef syntax used for closure

// class only needs to be declared once then used all over to wrap closures
// see http://en.wikipedia.org/wiki/Resource_Acquisition_Is_Initialization
class deferRAII {
public:
  deferRAII(simpleClosure cl) : runOnDestruction(cl) {}
  ~deferRAII() { runOnDestruction(); }
  
private:
  simpleClosure runOnDestruction;
};


void nestedFunc()
{
  deferRAII x( ^(){std::cout << "Invoked on exit!\n";} );
  std::cout << "Inside nestedFunc!\n";
  deferRAII x2( ^(){std::cout << "Invoked stacked on exit!\n";} );
}


int main(int argc, const char * argv[]) {
  
  std::cout << "Hello, World!\n";
  nestedFunc();
  std::cout << "Goodbye, World!\n";
  return 0;
}

Console output will be:
Hello, World!
Inside nestedFunc!
Invoked stacked on exit!
Invoked on exit!
Goodbye, World!