Solidity0.8.0-Ownable合约

// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.8.7;

contract Ownable {
    address public owner;
    
    constructor() {
        owner = msg.sender;
    }
    modifier onlyOwner() {  
        require(msg.sender == owner, "not owner");
        _; //函数中其他的代码在
    }

    ////函数中其他的代码在下划线这个位置运行
    function setOwner(address _newOwner) external onlyOwner {　　//切换合约管理员
        require(_newOwner != address(0), "invalid address"); //确认是否是0地址
        owner = _newOwner;

    }

    function onlyOwnerCanCallThisFunc() external onlyOwner {
        //code
    }
    function anyOneCanCall() external {
        //code
    }
}