Solidity: Encapsulation

 

// SPDX-License-Identifier: MIT
pragma solidity >= 0.7.0 < 0.9.0;

contract Number {
    uint private num = 4;

    function changeNum() public {
        num = 5;
    }

    function getNum() public view returns (uint) {
        return num;
    }
}


contract Caller {
    Number internal instance = new Number();

    function changeNumber() public {
        instance.changeNum();
    }

    function getNumber() public view returns(uint) {
        return instance.getNum();
    }
}