class Investment {}; 

Investment* creatInvestment(){...} // factory function to produce investment object

void main()
{
  Investment* pInv = creatInvestment();//call to get investment object
  
  ....
  
  delete pInv;           // sometime we forget this, happens   
}

//solution
void main()
{
   stid::auto_ptr<Investment> pInv(creatInvestment());
   
   ...
}//when pInv is destroied, auto_ptr will be released.

//problem with auto_ptr
//only one auto_ptr can point to one object
//if auto_ptr was assgined to another auto_ptr
//original auto_ptr would be null
//see following example:
void main()
{
   stid::auto_ptr<Investment> pInv1(creatInvestment());
   
    stid::auto_ptr<Investment> pInv2(pInv1); //pInv1 null
    
    pInv1 = pInv2;//pInv2 null
   ...
}

void main()
{
   stid::shared_ptr<Investment> pInv1(creatInvestment());
   
    stid::shared_ptr<Investment> pInv2(pInv1); //pInv1 null
    
    pInv1 = pInv2;//pInv2 null
   ...
}