// bad memory demo

#include <iostream>
using namespace std;

class Foo{
public:
  Foo(){data = 77;}
  int getData() const {return data;}
  void setData(int n){ data = n;}
private:
  int data;
};

// ERROR: pointer to local variable
Foo *someFN(){
  Foo temp;
  return &temp;
}



main(){

  // memory leak
  Foo *fp= new Foo;
  fp = new Foo;

  // no memory leak
  Foo *fp2= new Foo;
  delete fp2; fp2=0;
  fp2 = new Foo;


  // dangling pointer
  Foo *fp3 = new Foo;
  delete fp3;


  // dangling pointer
  Foo *fp4 = someFN();


  Foo *f_ptr = 0;
  f_ptr = new Foo();


  // Good: Always test pointer before accessing "something"
  //       via the pointer.
  // Issue: the test won't help if your pointers are not
  //        always pointing at 0 or the correct "object" 
  if (f_ptr){
    f_ptr -> setData(12);
    //(*f_ptr).setData(12); // equivalent, less common syntax
    cout << f_ptr -> getData();
  }

  int x = 100;

  int *a=0;
  a = new int[x]; // c++ to make a runtime sized-array
  
  int b[x]; // error until just recently (?)
  a[5] = 7;

  Foo *foos=0;
  foos = new Foo[15];



}