How to create a dynamic memory array in Solidity?

Question

I'm creating an ERC777 from a contract and I'm having trouble with the default operators. My code compiles fine but when I try to deploy it it doesn't work.

Here's a simplified version of my code

contract Amacoin is ERC777 {
  address public amaclicker;

  constructor(address[] memory defaultOperators) ERC777("Amacoin", "AMAC", defaultOperators) {
    amaclicker = defaultOperators[0];
  }
}

contract Amaclicker {
  Amacoin public amacoin;

  constructor() {
    address[] memory defaultOperators;
    defaultOperators[0] = address(this);
    amacoin = new Amacoin(defaultOperators);
  }
}

From my testing, it's the defaultOperators[0] = address(this); that doesn't work. Also just putting [address(this)] as the argument for Amacoin or defaultOperators doesn't work.

Edit: I still haven't found a solution but a workaround I've done is create a state variable and then delete it after creating Amacoin

Solution

Try this way. This should work.

address[] memory defaultOperators = new address[](1);
defaultOperators[0] = address(this);

Comments

[Patrick Collins]

Does this answer your question? Dynamic array in Solidity

[kowasaur]

This doesn't work TypeError: Member "push" is not available in address[] memory outside of storage.

[Sudipta Basak]

I have modified the answer. Check this one. @kowasaur

[nosbor]

But actually, this is not a dynamic array. As far as I know, the dynamic array is an array that is resizable i.e. has a push function. The mentioned here is not resizable. It's simply a declaration of static array with one element (n-elements) inside it. It is indeed a "dynamically allocated array" but NOT a "dynamic array".