C++:: Call class method using vector iterator?

Question

I have a class called Room, the Room class has setPrice and display function.

I stored room objects in a vector:

room.push_back(Room("r001", 1004, 2, "small"));
room.push_back(Room("r002", 1005, 2, "small"));
room.push_back(Room("r003", 2001, 4, "small"));
room.push_back(Room("r004", 2002, 4, "small"));

In my main function, i create a display function to display all rooms. Here is my code:

void displayRoom()
{
    vector<Room>::iterator it;
    for (it = room.begin(); it != room.end(); ++it) {
         *it.display(); // just trying my luck to see if it works
    }
}

But it does not call the Room's display method.

How do I call the Room(class)'s display method (no argument) and setPrice(1 argument) method?

score 12 · Accepted Answer · 2011-01-23 18:20:28Z

12

Dereferencing has higher priority than member access. You could add parens ((*it).display()), but you should just use the shortcut that was introduced long long ago (in C) for this: it->display().

Of course the same rule applies for pointers and everything else that can be dereferenced (other iterators, smart pointers, etc.).

edited Jan 23, 2011 at 18:20

answered Jan 23, 2011 at 18:03

user395760

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3 Comments

cpp_noob Over a year ago

Thanks for the answer and explanation. Chosen by workable solution and first answerer.

cpp_noob Over a year ago

If there anyway to call specific vector element's function. Like: room[2]->setPrice(200)

user395760 Over a year ago

@cpp_noob: room[2] gives you something. It it's an object, call the method as you would on any object (room[2].setPrice(200)). If that something needs to be dereferenced again, you need to dereference it - again (*(room[2])).setPrice(200) or room[2]->setPrice(200).

Alexandre C. · Accepted Answer · 2011-01-23 18:03:17Z

3

Try (*it).display() or simply it->display().

answered Jan 23, 2011 at 18:03

Alexandre C.

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Comments

Oliver Charlesworth · Accepted Answer · 2011-01-23 18:08:33Z

1

Iterators are a bit like pointers. So you want either:

it->display();

or:

(*it).display();

edited Jan 23, 2011 at 18:08

answered Jan 23, 2011 at 18:03

Oliver Charlesworth

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1 Comment

user395760 Over a year ago

The second is wrong, unless it's a vector of Room * (in the example, it isn't - and if it was, the first is wrong instead).

user11135761 · Accepted Answer · 2019-03-01 11:36:59Z

0

Using Vector, you can also use classic form

for(size_t x = 0; x < room.size(); x++) {
    room[x].display(); //for objects
    //room[x]->display(); //for pointers
}

answered Mar 1, 2019 at 11:36

user11135761

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