Pointers to objects in C++

Question

I am trying to get the hang of C++ pointers and objects, through a small project implementing a simple Vehicle Routing Problem. Even though my code is currently working, I can't shake the feeling that my approach is completely wrong. What bugs me, are snippets of code such as :

std::map<const Route*, double>::iterator it = quantities.begin();
if ((*(*(it->first)).getDestination()).getDemand() > (*(*(it->first)).getDeparture()).getSupply())

The pointer hell situation in the if condition is the result of the get methods returning pointers to already created objects. The methods being called are :

const Departure* Route::getDeparture() const {
    return departure;
};

const Destination* Route::getDestination() const {
    return destination;
};

and

int Destination::getDemand() const {
    return demand;
};

int Departure::getSupply() const {
    return supply;
};

Am I completely off track here, am i missing something or is this type of situtation something normal?

Rafal R · Accepted Answer · 2012-04-03 18:47:12Z

2

To increase readability you can change *s to ->:

if(it->first->getDestination()->getDemand() > it->first->getDeparture()->getSupply())

Also, if you aren't going to give up ownership of that object (and you aren't, in this case) it is better to return by const reference:

const Departure& Route::getDeparture() const {
  return *departure;
};

and use ., not ->:

if(it->first->getDestination().getDemand() > it->first->getDeparture().getSupply())

edited Apr 3, 2012 at 18:47

answered Apr 3, 2012 at 18:38

Rafal R

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Cheers and hth. - Alf · Accepted Answer · 2012-04-03 18:37:07Z

2

instead of (*p).x write p->x.

answered Apr 3, 2012 at 18:37

Cheers and hth. - Alf

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1 Comment

Spyros Mandekis Over a year ago

and just chain as iterator->member->method1->method2 etcetera?

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