CODEWITHSUNDEEP
c++objectdynamic
icegas
icegas

Reputation: 81

How to initialize an object dynamically in the program?

How to initialize object dynamically in the program without inheritance in c++? For example i Have class A and class B. And depend on condition i need to create instance of object but i don't know exactly what object i need to create, it depends on information that user input;

Example code:

int i;
cin>>i>>endl;
void *obj;
if(i)
    obj = new A();
else
    obj = new B();

Upvotes: 1

Views: 182

Answers (2)

nefas
nefas

Reputation: 1130

You can use std::any or std::variant depending on your needs.

Casting a pointer to void* is (most of the time) a bad idea because you loose the type of the object and you have to deal with raw pointer. Which means that you have to manage resources, call the right destructor... any and variant do that for you.

I would recommend using variant and not any, unless you have a specific need for any because variantgive you more control over the type: your value can have only a limited list of type.

Upvotes: 1

Manish Sogi
Manish Sogi

Reputation: 261

If you do not have limitation of taking pointers then take two pointers of both classes and initialize the one according to input.

int i;
A *a_ptr;
B *b_ptr;
cin>>i>>endl;
if(i)
    a_ptr = new A();
else
    b_ptr = new B();

Upvotes: 1

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