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first_steps_in_solidity_blockchain...001_first_steps.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import { ERC721 } from "@openzeppelin/contracts/token/ERC721/ERC721.sol";

contract FirstContract is ERC721 {
    address owner;

    constructor(string memory _name, string memory _symbol) ERC721(_name, _symbol) {
        owner = msg.sender;
    }
}

first_steps_in_solidity_blockchain...002_variables_and_modifiers.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract VariablesAndModifiers {
    uint256 a;
    uint8 public b = 3;

    int256 c;
    int8 public d = -32;
    int e = 65;

    string str;
    string public str_public = 'This is a public variable';
    string private str_private = 'This is a private variable';

    bool boolean;
    bool public boolean_public = true;
    bool private boolean_private = false;

    bytes32 first_bytes;
    bytes4 second_bytes;
    bytes1 bytes_1;

    bytes32 public hashing_keccak256 = keccak256(abi.encodePacked('Salva', uint(10), 0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2));
    bytes32 public hashing_sha256 = sha256(abi.encodePacked('Salva'));
    bytes20 public hashing_ripemd160 = ripemd160(abi.encodePacked('Salva'));


    address my_address;
    address public address1 = 0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2;
    address public address2 = msg.sender;

    enum options {
        ON,
        OFF
    }

    options state;
    options constant defaultChoise = options.OFF;

    function turnOn() public {
        state = options.ON;
    }

    function turnOff() public {
        state = options.OFF;
    }

    function displayState() public view returns (options) {
        return state;
    }
}

first_steps_in_solidity_blockchain...003_data_structures.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract DataStructures {
    struct Customer {
        uint256 id;
        string name;
        string email;
    }

    Customer customerOne = Customer(1, "Salva", "[email protected]");
    
    uint256 [5] public fixedListUInts = [1, 2, 3, 4, 5];

    uint256 [] dynamicListUInts;

    Customer [] public dynamicCustomerList;

    function modifierCustomerList (uint256 _id, string memory _name, string memory _email) public  {
        Customer memory randomCustomer = Customer(_id, _name, _email); 
        dynamicCustomerList.push(randomCustomer);
    }

    mapping (address => uint256) public addressUInt;
    mapping (string => uint256 []) public stringUIntList;
    mapping (address => Customer) public addressCustomer;

    function assignNumber (uint256 _number) public  {
        addressUInt[msg.sender] = _number;
    }

    function assignList (string memory _name, uint256 _number) public {
        stringUIntList[_name].push(_number);
    }

    function assignAddressCustomer(uint256 _id, string memory _name, string memory _email) public {
        addressCustomer[msg.sender] = Customer(_id, _name, _email);
    }
}

first_steps_in_solidity_blockchain...004_functions.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract Functions {
    function getName() public pure returns (string memory) {
        return 'Salva';
    }

    uint256 x = 100;
    function getNumber() public view returns (uint256) {
        return x*2;
    }

    
}

first_steps_in_solidity_blockchain...005_payable.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract EthSend {
    constructor() payable {}
    receive() external payable { }

    event sendStatus(bool);
    event callStatus(bool, bytes);

    function sendViaTransfer(address payable _to) public payable {
        _to.transfer(1 ether);
    }

    function sendViaSend(address payable _to) public payable {
        bool sent = _to.send(1 ether);

        emit sendStatus(sent);
        require(sent == true, 'Shipment has failed');
    }

    function sendViaCall(address payable _to) public payable {
        (bool success, bytes memory data) = _to.call{value: 1 ether}('');

        emit callStatus(success, data);
        require(success == true, 'Shipment has failed');
    }
}

contract EthReceiver {
    event log(uint amount, uint gas);

    receive() external payable {
        emit log(address(this).balance, gasleft());
    } 
}

first_steps_in_solidity_blockchain...006_fallback_receive.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract FallbackReceive {
    event log(string _name, address _sender, uint _amount, bytes _data);

    fallback() external payable {
        emit log('Fallback', msg.sender, msg.value, msg.data);
    }

/*
    receive() external payable {
        emit log('Receive', msg.sender, msg.value, '');
    }
*/
}

first_steps_in_solidity_blockchain...007_math_operations.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract Math {
    function sum(uint a, uint b) public pure returns (uint) {
        return a+b;
    }

    function rest(uint a, uint b) public pure returns (uint) {
        return a-b;
    }

    function multipler(uint a, uint b) public pure returns (uint) {
        return a*b;
    }

    function divider(uint a, uint b) public pure returns (uint) {
        return a/b;
    }

    function exponential(uint a, uint b) public pure returns (uint) {
        return a**b;
    }

    function module(uint a, uint b) public pure returns (uint) {
        return a%b;
    }
}

first_steps_in_solidity_blockchain...008_loops_conditionals.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract LoopsCondtionals {
    function sum(uint _number) public pure returns (uint) {
        uint temporalSum = 0;

        for (uint i = 0; i < _number; i++) {
            temporalSum += i;
        }

        return temporalSum;
    }

    function sumOdd() public pure returns (uint) {
        uint temporalSum = 0;
        uint counter = 0;
        uint counterOdd = 0;

        while (counterOdd < 10) {
            if (counter % 2 != 0) {
                temporalSum += counter;
                counterOdd++;
            }

            counter++;
        }

        return temporalSum;
    }

    function sumOrRest(string memory operation, uint a, uint b) public pure returns (uint) {
        bytes32 hashedOperation = keccak256(abi.encodePacked(operation));
        bytes32 sumHashedOperation = keccak256(abi.encodePacked('suma'));
        if (hashedOperation == sumHashedOperation) {
            return a+b;
        }

        return a-b;
    }
}

first_steps_in_solidity_blockchain...009_advanced_functions.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract Food {
    struct DinnerDish {
        string name;
        string ingredients;
    }

    DinnerDish [] public menu;

    function newMenu(string memory _name, string memory _ingredients) internal {
        menu.push(DinnerDish(_name, _ingredients));
    }
}

contract Hamburger is Food {
    address public owner;

    constructor () {
        owner = msg.sender;
    }

    function cookHamburger(string memory _ingredients, uint __units) external {
        require(__units <= 5, "Ops, you cannot order 5 or more hamburgers");
        newMenu('Hamburger', _ingredients);
    }

    modifier onlyOwner () {
        require(owner == msg.sender, "You do not have permissions to execute this function");
        _;
    }

    function hasPrivateNumber(uint _number) public view onlyOwner returns (bytes32) {
        return keccak256(abi.encodePacked(_number));
    }
}

first_steps_in_solidity_blockchain...010_contract_factory.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract ContractFactory {
    mapping (address => address) public personalContract;

    function factory() public {
        address newContract = address(
            new SingleContract(
                msg.sender,
                address(this)
            )
        );

        personalContract[msg.sender] = newContract;
    }
}

contract SingleContract {
    Owner public owner;
    struct Owner {
        address _owner;
        address _smartContractFactory;
    }

    constructor(address _account, address _contractAddress) {
        owner._owner = _account;
        owner._smartContractFactory = _contractAddress;
    }
}

first_steps_in_solidity_blockchain...011_use_openzeppelin_erc20.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

// https://docs.openzeppelin.com/contracts/4.x/erc20
import "@openzeppelin/[email protected]/token/ERC20/ERC20.sol";

contract GLDToken is ERC20 {
    constructor(uint256 initialSupply) ERC20("Gold", "GLD") {
        _mint(msg.sender, initialSupply);
    }
}

first_steps_in_solidity_blockchain...012_create_a_contract_erc20.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

interface IERC20 {
    function totalSupply() external view returns (uint256);
    
    function balanceOf(address account) external view returns (uint256);
    
    function transfer(address to, uint256 amount) external returns (bool);
    
    function allowance(address owner, address spender) external view returns (uint256);
    
    function approve(address spender, uint256) external returns (bool);
    
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);

    event Transfer(
        address indexed from,
        address indexed to,
        uint256 value
    );

    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}

contract ERC20 is IERC20 {
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    uint256 private _totalSupply;
    string private _name;
    string private _symbol;

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    function name() public view virtual returns (string memory) {
        return _name;
    }

    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }

    function decimals() public view virtual returns (uint8) {
        return 18;
    }

    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = msg.sender;
        _transfer(
            owner,
            to,
            amount
        );

        return true;
    }

    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = msg.sender;

        _approve(
            owner,
            spender,
            amount
        );

        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override  returns (bool) {
        address spender = msg.sender;

        _spendAllowance(
            from,
            spender,
            amount
        );
        
        _transfer(
            from,
            to,
            amount
        );

        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = msg.sender;

        _approve(owner, spender, _allowances[owner][spender] + addedValue);

        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = msg.sender;
        uint256 currentAllowance = _allowances[owner][spender];

        require(currentAllowance >= subtractedValue, "[ERC20] Decrease allowance below zero");
        unchecked {
            _approve(
                owner,
                spender,
                currentAllowance - subtractedValue
            );
        }


        return true;
    }

    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "[ERC20] Transfer from the zero address");
        require(to != address(0), "[ERC20] Transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "[ERC20] Transfer amount exceeds balance");
        
        unchecked {
            _balances[from] = fromBalance - amount;
        }

        _balances[to] += amount;
        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    function _mint(address account, uint amount) internal virtual {
        require(account != address(0), "[ERC20] Mint to the zero address");
        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        _balances[account] += amount;

        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "[ERC20] Burn from the zero address");
        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        
        require(accountBalance >= amount, "[ERC20] Burn amount exceeds balance");

        unchecked {
            _balances[account] = accountBalance - amount;
        }

        emit Transfer(account, address(0), amount);
        _afterTokenTransfer(account, address(0), amount);
    }

    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "[ERC20] Approve from the zero address");
        require(spender != address(0), "[ERC20] Approve to the zero address");

        _allowances[owner][spender] = amount;

        emit Approval(owner, spender, amount);
    }

    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "[ERC] insufficient allowance");

            unchecked {
                _approve(owner, spender, amount);
            }
        }
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

first_steps_in_solidity_blockchain...013_use_custom_erc20.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import './012_create_a_contract_erc20.sol';

contract CustomERC20 is ERC20 {
    constructor() ERC20("Salva", "SBR") {}

    function createTokens() public {
        _mint(msg.sender, 1000);
    }
}

first_steps_in_solidity_blockchain...014_token_generation_erc721.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "@openzeppelin/[email protected]/token/ERC721/ERC721.sol";
import "@openzeppelin/[email protected]/utils/Counters.sol";

contract CustomERC721 is ERC721 {
    using Counters for Counters.Counter;
    Counters.Counter private _tokenIds;

    constructor(string memory _name, string memory _symbol) ERC721(_name, _symbol) {}

    function sendNFT(address _account) public {
        _tokenIds.increment();

        uint256 newItemId = _tokenIds.current();
        
        _safeMint(_account, newItemId);
    }
}