reentrancyAttack.sol

/* Bad */
function badWithdraw(uint amounts) public {
    require(amounts <= balances[msg.sender]); // 1.𝗖𝗛𝗘𝗖𝗞
    (bool success, bytes memory data)
		= msg.sender.call{value: amounts}(""); // 3.𝗜𝗡𝗧𝗘𝗥𝗔𝗖𝗧𝗜𝗢𝗡
    require(success);
    balances[msg.sender] - amounts; // 2.𝗘𝗙𝗙𝗘𝗖𝗧𝗦
  }

/* Better */
function goodWithdraw(uint amounts) public {
    require(amounts <= balances[msg.sender]); // 1.𝗖𝗛𝗘𝗖𝗞
    balances[msg.sender] - amounts; // 2.𝗘𝗙𝗙𝗘𝗖𝗧𝗦
    (bool success, bytes memory data)
		= msg.sender.call{value: amounts}(""); // 3.𝗜𝗡𝗧𝗘𝗥𝗔𝗖𝗧𝗜𝗢𝗡
    require(success); 
  }