OOP · medium

22. virtual & override

Polymorphism in Solidity.

Base `Animal` has `function sound() public pure virtual returns (string memory) { return "..."; }`. Child `Dog` overrides it to return `"woof"`.

Required in your answer: contract Dog is Animaloverride returns (string memory)woof

Compiles with solc in your browser

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract Animal {
    function sound() public pure virtual returns (string memory) { return "..."; }
}
// TODO contract Dog is Animal

Output appears here.

← 21. Inheritance 23. Abstract contracts & interfaces →