AyDeveloper

// SPDX-License-Identifier: GPL-3.0
// using the latest version 
pragma solidity >=0.7.0 < 0.9.0;
import "hardhat/console.sol";

// vulnerable Bank
contract Bank {
    /*Contract that stores user balances. This is the vulnerable contract. This contract contains 
    the basic actions necessary to interact with its users, such as: get balance, add to balance,
    and withdraw balance */

AyDeveloper

// This line tells us that the source code is licensed under the GPL version 3.0.
// SPDX-License-Identifier: GPL-3.0

// This line specifies that the source code is written for Solidity compiler version 0.7.0 
// or a newer version of the language up to, but not including version 0.9.0.
pragma solidity >=0.7.0 <0.9.0;

// A contract is declared using a contract keyword followed by the contract's name
contract Storage {

AyDeveloper

pragma solidity ^0.8.0;

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
}

contract Token {
    
    // state variable called ERC20ContractAddress that represents the address of the ERC20 contract

AyDeveloper

contract Owner {
    address owner;
    function setOwner() public { 
        owner = msg.sender; 
    }
}

contract Suicide is Owner {
    function destroy() public {
        if (msg.sender == owner) selfdestruct(payable(owner));

AyDeveloper

contract A {}
contract B {}
contract C is A, B {}


// Setting Constructor in base contract

contract A {
    uint a;

AyDeveloper

// SPDX-License-Identifier: Unlicensed
pragma solidity ^0.8.0;

abstract contract HelloWorld {
   string public message;
    constructor(string memory _message){
       message = _message;
    }

AyDeveloper

pragma solidity ^0.8.0;

contract DepositEther {
    event Deposit(
        address indexed _from,
       	uint indexed _id,
        uint _value
    );

AyDeveloper

library arithmetic {
    function multiply(uint _a, uint _b) returns (uint) {
        return _a  * _b;
    }
}

contract C {
    uint timesUp;

AyDeveloper

library arithmetic {
    function add(uint _a, uint _b) returns (uint) {
        return _a + _b;
    }
}

contract C {
    using arithmetic for uint;
    

AyDeveloper

pragma solidity ^0.8.0;

contract Donation {
    // input your default donor address
    address public donor = 0x5B38Da6a701c568545dCfcB03FcB875f56beddC4;
    uint constant DONATION_FEE = 2 ether;

    modifier onlyDonor() {
    require(msg.sender == donor,"Only buyer can call this.");