Dynamically create an array of object pointers

Question

I have a class called "poly". I want to dynamically create an array of pointers to poly objects. The variable "totalPolynomials" holds the number of poly objects.

Here is my code to declare the array:

poly **polyPtr;                         
polyPtr = new poly *[totalPolynomials];

I successfully create poly objects, but don't know how to store their pointers in the array one after another...

I suggest to use std::vector<std::unique_ptr<poly>> (or std::vector<poly*>). — Jarod42
– Jarod42, Commented Apr 20, 2014 at 15:09
I would advise against this. Do what @Jarod42 says, instead. — Lightness Races in Orbit
– Lightness Races in Orbit, Commented Apr 20, 2014 at 15:11

riklund · Accepted Answer · 2014-04-20 15:03:49Z

4

If you are creating them and then want to store them, you can do something like

poly ** polyPtr;
polyPtr = new poly* [totalPolynomials];

for(int i = 0; i<totalPolynomials; ++i)
{
    polyPtr[i] = new poly(arguments);
}

answered Apr 20, 2014 at 15:03

riklund

1,0812 gold badges8 silver badges16 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

László Papp · Accepted Answer · 2014-04-20 15:15:30Z

1

You are not actually setting the pointers in the array, so a a demonstration, you would be writing something like this:

poly** polyPtr = new poly*[totalPolynomials];
for(int i = 0; i < totalPolynomials; ++i)
    // You may need to pass constructor arguments here.
    polyPtr[i] = new poly();
    // or polyPtr[i] = myOtherPointer; in case you just wanna share it.

Storing you pointers would be similar instead of allocating memory for new ones. Basically, you would need to replace the new with your pointers.

No answer can go without the warning that you should consider higher-level data and memory management than this when programming in C++ for your productivity and mental well-being.

So, I would suggest using something like this:

std::vector<std::shared_ptr<poly>>

or

std::vector<std::unique_ptr<poly>>

Depending on your exact desire.

edited Apr 20, 2014 at 15:15

answered Apr 20, 2014 at 15:08

László Papp

53.5k40 gold badges118 silver badges142 bronze badges

1 Comment

riklund Over a year ago

I don't think he is trying to create a 2D array, but rather a 1D array of pointers...

Collectives™ on Stack Overflow

Dynamically create an array of object pointers

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related