Created using remix-ide: Realtime Ethereum Contract Compiler and Runtime. Load this file by pasting this gists URL or ID at https://remix.ethereum.org/#version=soljson-v0.8.7+commit.e28d00a7.js&optimize=false&runs=200&gist=

README.txt

REMIX DEFAULT WORKSPACE

Remix default workspace is present when:
i. Remix loads for the very first time 
ii. A new workspace is created
iii. There are no files existing in the File Explorer

This workspace contains 3 directories:

1. 'contracts': Holds three contracts with different complexity level, denoted with number prefix in file name.
2. 'scripts': Holds two scripts to deploy a contract. It is explained below.
3. 'tests': Contains one Solidity test file for 'Ballot' contract & one JS test file for 'Storage' contract

SCRIPTS

The 'scripts' folder contains two example async/await scripts for deploying the 'Storage' contract.
For the deployment of any other contract, 'contractName' and 'constructorArgs' should be updated (along with other code if required). 

Also, there is a script containing some unit tests for Storage contract inside tests directory.

To run a script, right click on file name in the file explorer and click 'Run'. Remember, Solidity file must already be compiled.
Output from script will appear in remix terminal.

Please note, 'require' statement is supported in a limited manner for Remix supported modules.
For now, modules supported by Remix are ethers, web3, swarmgw, chai, remix and hardhat only for hardhat.ethers object/plugin.
For unsupported modules, an error like this will be thrown: '<module_name> module require is not supported by Remix IDE will be shown.'

contracts...1_Storage.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;

/**
 * @title Storage
 * @dev Store & retrieve value in a variable
 * @custom:dev-run-script ./scripts/deploy_with_ethers.ts
 */
contract Storage {

    uint256 number;

    /**
     * @dev Store value in variable
     * @param num value to store
     */
    function store(uint256 num) public {
        number = num;
    }

    /**
     * @dev Return value 
     * @return value of 'number'
     */
    function retrieve() public view returns (uint256){
        return number;
    }
}

contracts...2_Owner.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;

import "hardhat/console.sol";

/**
 * @title Owner
 * @dev Set & change owner
 */
contract Owner {

    address private owner;
    
    // event for EVM logging
    event OwnerSet(address indexed oldOwner, address indexed newOwner);
    
    // modifier to check if caller is owner
    modifier isOwner() {
        // If the first argument of 'require' evaluates to 'false', execution terminates and all
        // changes to the state and to Ether balances are reverted.
        // This used to consume all gas in old EVM versions, but not anymore.
        // It is often a good idea to use 'require' to check if functions are called correctly.
        // As a second argument, you can also provide an explanation about what went wrong.
        require(msg.sender == owner, "Caller is not owner");
        _;
    }
    
    /**
     * @dev Set contract deployer as owner
     */
    constructor() {
        console.log("Owner contract deployed by:", msg.sender);
        owner = msg.sender; // 'msg.sender' is sender of current call, contract deployer for a constructor
        emit OwnerSet(address(0), owner);
    }

    /**
     * @dev Change owner
     * @param newOwner address of new owner
     */
    function changeOwner(address newOwner) public isOwner {
        emit OwnerSet(owner, newOwner);
        owner = newOwner;
    }

    /**
     * @dev Return owner address 
     * @return address of owner
     */
    function getOwner() external view returns (address) {
        return owner;
    }
}

contracts...3_Ballot.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;

/** 
 * @title Ballot
 * @dev Implements voting process along with vote delegation
 */
contract Ballot {
   
    struct Voter {
        uint weight; // weight is accumulated by delegation
        bool voted;  // if true, that person already voted
        address delegate; // person delegated to
        uint vote;   // index of the voted proposal
    }

    struct Proposal {
        // If you can limit the length to a certain number of bytes, 
        // always use one of bytes1 to bytes32 because they are much cheaper
        bytes32 name;   // short name (up to 32 bytes)
        uint voteCount; // number of accumulated votes
    }

    address public chairperson;

    mapping(address => Voter) public voters;

    Proposal[] public proposals;

    /** 
     * @dev Create a new ballot to choose one of 'proposalNames'.
     * @param proposalNames names of proposals
     */
    constructor(bytes32[] memory proposalNames) {
        chairperson = msg.sender;
        voters[chairperson].weight = 1;

        for (uint i = 0; i < proposalNames.length; i++) {
            // 'Proposal({...})' creates a temporary
            // Proposal object and 'proposals.push(...)'
            // appends it to the end of 'proposals'.
            proposals.push(Proposal({
                name: proposalNames[i],
                voteCount: 0
            }));
        }
    }
    
    /** 
     * @dev Give 'voter' the right to vote on this ballot. May only be called by 'chairperson'.
     * @param voter address of voter
     */
    function giveRightToVote(address voter) public {
        require(
            msg.sender == chairperson,
            "Only chairperson can give right to vote."
        );
        require(
            !voters[voter].voted,
            "The voter already voted."
        );
        require(voters[voter].weight == 0);
        voters[voter].weight = 1;
    }

    /**
     * @dev Delegate your vote to the voter 'to'.
     * @param to address to which vote is delegated
     */
    function delegate(address to) public {
        Voter storage sender = voters[msg.sender];
        require(!sender.voted, "You already voted.");
        require(to != msg.sender, "Self-delegation is disallowed.");

        while (voters[to].delegate != address(0)) {
            to = voters[to].delegate;

            // We found a loop in the delegation, not allowed.
            require(to != msg.sender, "Found loop in delegation.");
        }
        sender.voted = true;
        sender.delegate = to;
        Voter storage delegate_ = voters[to];
        if (delegate_.voted) {
            // If the delegate already voted,
            // directly add to the number of votes
            proposals[delegate_.vote].voteCount += sender.weight;
        } else {
            // If the delegate did not vote yet,
            // add to her weight.
            delegate_.weight += sender.weight;
        }
    }

    /**
     * @dev Give your vote (including votes delegated to you) to proposal 'proposals[proposal].name'.
     * @param proposal index of proposal in the proposals array
     */
    function vote(uint proposal) public {
        Voter storage sender = voters[msg.sender];
        require(sender.weight != 0, "Has no right to vote");
        require(!sender.voted, "Already voted.");
        sender.voted = true;
        sender.vote = proposal;

        // If 'proposal' is out of the range of the array,
        // this will throw automatically and revert all
        // changes.
        proposals[proposal].voteCount += sender.weight;
    }

    /** 
     * @dev Computes the winning proposal taking all previous votes into account.
     * @return winningProposal_ index of winning proposal in the proposals array
     */
    function winningProposal() public view
            returns (uint winningProposal_)
    {
        uint winningVoteCount = 0;
        for (uint p = 0; p < proposals.length; p++) {
            if (proposals[p].voteCount > winningVoteCount) {
                winningVoteCount = proposals[p].voteCount;
                winningProposal_ = p;
            }
        }
    }

    /** 
     * @dev Calls winningProposal() function to get the index of the winner contained in the proposals array and then
     * @return winnerName_ the name of the winner
     */
    function winnerName() public view
            returns (bytes32 winnerName_)
    {
        winnerName_ = proposals[winningProposal()].name;
    }
}

contracts...address.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Address {
    address public WETH = 0x5B38Da6a701c568545dCfcB03FcB875f56beddC4;
    address payable public Vault = payable(0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2);
    constructor() {}
}

contracts...arrays.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Arrays {

    string[] public eggBox = ["egg1", "egg2", "egg3"];

    constructor() {}

    function dynamicArrays() public pure returns (uint256[] memory) {
        uint256[] memory luckyNumber = new uint256[](5);
         // 0,0,0,7,0
        luckyNumber[3] = 7;
        luckyNumber[5] = 1;

        return luckyNumber;
    }
}

contracts...bool.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Bool {
    constructor() {
        
    } // 建構式
}

contracts...bytes.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Bytes {
    // 8bits = 1byte, 4bits = 1/2byte
    bytes1 public b1 = 0x01;
    bytes2 public b2 = 0x01f2;
    bytes3 public b3 = 0x01f273;
    bytes4 public b4 = 0x01f273a0;
    constructor() {}
}

contracts...contract.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Car {
    string public color = "red";

    constructor() {}
}

contract Contract {
    Car car;

    constructor() {
        car = Car()
    }

    function getCarColor() {
        return 
    }
}

contracts...enums.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Enums {
    // keyword enum
    enum State {
        TODO, // 0
        COMPLETED, // 1
        PAUSED // 2
    }
    //型別 //公開                   // Enum
    bool public isZero = uint256(State.TODO) == 0; // true
    bool public isOne = uint256(State.COMPLETED) == 1; // false
    bool public isTwo = uint256(State.PAUSED) == 2;

    constructor() {}
}

contracts...function.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Function {
    constructor() {}
    // public / internal / external
    function callMyMintNFT() public payable returns (string memory) {
        return _mintNFT();
    }

    function _mintNFT() internal pure returns (string memory) {
        return "Mint Success.";
    }

    function getBalance() public view returns (uint256, string memory, address) {
        return (address(this).balance, "Hello World", 0x5B38Da6a701c568545dCfcB03FcB875f56beddC4);
    }
}

contracts...int.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Integer {
    uint16 public myNumber = 256;
    int256 public myNumber_int = -270;
    constructor() {}
}

contracts...mapping.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Mapping {
    mapping(address => uint256) public balances;

    constructor() {
        balances["msg"] = 1;
        balances[0x17F6AD8Ef982297579C203069C1DbfFE4348c372] = 15;
    }
}

contracts...myToken.sol

// contracts/GLDToken.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract MyToken is ERC20 {
    constructor(uint256 initialSupply) ERC20("MyToken", "MT") {
        _mint(msg.sender, initialSupply);
    }
}

contracts...myToken721.sol

// contracts/GameItem.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/utils/Counters.sol";

contract MyNFT is ERC721 {
    constructor() ERC721("MyNFT", "MNFT") {}

    function mint(uint256 tokenId) public {
        _mint(msg.sender, tokenId);
    }
}

contracts...Operators.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;
         // 運算子
contract Operators {
    constructor() {}

    function add(uint256 num1, uint256 num2) public pure returns (uint256) {
        return num1 + num2;
    }

    function sub(int256 num1, int256 num2) public pure returns (int256) {
        return num1 - num2;
    }

    function mul(uint256 num1, uint256 num2) public pure returns (uint256) {
        return num1 * num2;
    }

    function div(uint256 num1, uint256 num2) public pure returns (uint256) {
        return num1 / num2;
    }

    function count1(uint256 num1) public pure returns (uint256) {
        return ++num1;  
    }

    function equal(uint256 num1, uint256 num2) public pure returns (bool) {
        return num1 == num2;
    }

    function GT(uint256 num1, uint256 num2) public pure returns (bool) {
        return num1 > num2;
    }

    function GTE(uint256 num1, uint256 num2) public pure returns (bool) {
        return num1 >= num2;
    }
 }

contracts...string.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract String {
    string public message = "Hello World"; // 字串要用雙引號 "  "
    string public name = "KryptoCamp";
    constructor() {}
}

contracts...struct.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Struct {
    // keyword
    struct Car {
        uint256 width;
        string color;
        string name;
    }

    Car public myCar;
    Car public myCar2;

    constructor() {
            //uint256 //string  //string
        myCar = Car(300, "black", "CC");
        myCar2 = Car(200, "red", "CC2");
    }

    function getCarColor() public view returns (string memory) {
        // 取得我的車子顏色
        return myCar2.color;
    }
}

contracts...variables.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

contract Variables {
    bool public isActive = true;
    uint256 public num = 200;
    address public myWallet = 0x1CA43B645886C98d7Eb7d27ec16Ea59f509CBe1a;

    constructor() {}

    function flipActive() public {
        isActive = !isActive;
    }

    function active() public view returns (string memory) {
        if(isActive) {
            return "is open!";
        } else {
            return "is close!";
        }
    }
}