StorageWithOwnership.sol

StorageWithOwnership.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;

contract StorageWithOwnership {
    uint256 number;
    address public owner;

    constructor() {
        owner = msg.sender;
    }

    modifier onlyOwner() {
        require(msg.sender == owner, "Not the contract owner");
        _;
    }

    function transferOwnership(address newOwner) public onlyOwner {
        require(newOwner != address(0), "New owner is the zero address");
        owner = newOwner;
    }

    function store(uint256 num) public onlyOwner {
        number = num;
    }

    function retrieve() public view returns (uint256) {
        return number;
    }
}