How to access state variables in other contracts in solidity?

Question

I learned how to call the function of another contract in solidity. However, I can not find any approach to access to the state variables as follow attempt, so how to do it in solidity ^0.8.17?

contract A {
    uint public x = 3;
}



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

import "./A.sol";

contract B {
    A public contractA ;

    function getAcontractState() public{
        contractA = new A();
        uint y = contractA.x; // error is here.
    }
}   

Answer 1

interface IContractA {
 uint public x;
}

contract B {

    function getContractAState() public returns (uint256){
        IContractA contractA = IContractA(contractAAddress);
        uint256 y = contractA.x()
        return y;
    }
}

Create an interface for the ContractA and interact with it through the interface.

Answer 2

Public fields in contracts become externally accessible by their getters, which are auto generated by Solidity with the same name.

Example:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

contract A {
    uint public x = 3;
}

contract B {
    A public contractA ;

    function getAcontractState() public returns (uint256){
        contractA = new A();
        uint256 y = contractA.x(); // error was here.
        return y;
    }
}

Hope this solves your problem.