Understanding Boolean

Solidity, as with any programming language, provides a Boolean data type. The bool data type can be used to represent scenarios that have binary results, such as true or false, and 1 or 0. The valid values for this data type are true and false. Note that bool data types in Solidity cannot be converted to integers as they can in other programming languages. It's a value type, and any assignment to other Boolean variables creates a new copy. The default value for bool in Solidity is false.

A bool data type is declared and assigned a value, as shown in the following code:

bool isPaid = true;

It can be modified within contracts and can be used in both incoming and outgoing parameters and the return value, as shown in the following code listing:

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;
contract BoolContract {
    bool isPaid = true;
    
    function manageBool...