使用引用在对象内包含对象向量

Question

I am trying to establish the relationship between two different classes with my code. I have a class Object and a Class Interface. The Object class can hold any number of Interfaces, of which I have chosen to store within a vector of unique pointers.

My Object class definition is:

#ifndef BASE_OBJECT
#define BASE_OBJECT

#include <vector>
#include <memory>

#include "./Interface.hxx"

class Object
{
/*****************
    Properties
******************/
//General
std::string ObjectType;

//Interfaces - All objects have at least one sender or receiver
//(otherwise it does nothing)
//Senders
typedef std::vector<std::unique_ptr<Interface>> Senders;

//Receivers
typedef std::vector<std::unique_ptr<Interface>> Receivers;

/**********************
    Member functions
**********************/
public:
    //Standard constructor
    Object(void);

    //Copy constructor
    Object(const Object& from);

    //Virtual destructor
    virtual ~Object(void);

    //Add an interface
    void add_interface(std::string type);
};

#endif

I haven't included my interface class, as it doesn't define anything as yet. When trying to add an interface to my Object, I call the following routine from my main function:

//Add interface to object
MyObject->add_interface("Sender");

Which calls the routine add_interface:

//Add an interface to the object
void Object::add_interface(std::string type)
{
if (type.compare("Sender")){
    auto intf = std::unique_ptr<Interface>(new Interface);
    this->Senders.push_back(std::move(intf));
}
else if (type.compare("Receiver")){
    auto intf = std::unique_ptr<Interface>(new Interface);
    this->Receivers.push_back(std::move(intf));
}
else{
    //Throw exception
}
}

Currently within visual studio express, the "Senders" and "Receivers" is highlighted with the warning "Error: type name is not allowed", and upon compilation I get the following error:

'function-style cast': illegal as right side of -> operator.

I am new to smart pointers and OOP, so I am not really sure what I am doing wrong here. Can anyone please explain my mistake? Many thanks in advance.

Answer 1

Senders and Receivers in your code are just types, not fields. You should declare two fields, eg: Senders senders; Receiers receivers

Answer 2

Senders and Receivers are typedef s within your Object class, not members.

Objects (or variables) and types cannot generally have the same name, in the same scope

Answer 3

You have:

typedef std::vector<std::unique_ptr<Interface>> Senders;
typedef std::vector<std::unique_ptr<Interface>> Receivers;

Senders and Receivers are types, indeed. They are not objects. Hence, this->Senders and this->Receivers does not make sense.

You need to use:

Senders senders;     // A variable that can hold senders
Receivers receivers; // A variable that can hold receivers.

And then use:

this->senders.push_back(std::move(intf));

and

this->receivers.push_back(std::move(intf));