Welcome to my learning feedback repo for 30 Days of Solidity!
🥕Every day in june 2025.
#BuildinPublic
#Solidity
@HerstoryWeb3
@0xbalala
@0xqiuqiuu
@audaciousSneha
📑Day {01} in becoming a Solidity developer
✔️理解.sol合约结构
✔️自定义类型为uint256的N*变量用于存储数字
✔️调用click()公共函数用于计数
😊使用remix 集成开发环境进行在线编译与部署合约的体验很好
📑Day {02} in becoming a Solidity developer
✔️引用类型RT(e.g. string)不同于值类型VT，在使用时必须指定数据位置DL
✔️函数的返回规则如图，搭配return关键词食用
✔️view禁改，pure禁读禁改，也意味着更节油
📑Day {03} in becoming a Solidity developer
✔️类似于PY，Solidity使用Array和Mapping处理结构数据
✔️declare Array Type[size不填为dynamic] 变量名 P.S.多维数组必须同类型
✔️append Array .push(变量) P.S.用new T[](n)重设memory数组大小
✔️declare Mapping mapping(KeyType KeyName*可选 => ValueType ValueName*可选) 变量名
🤔可以用for循环遍历mapping字典的value
// ================================================
// 返回所有候选人的票数
// ================================================
function getAllVoteCounts() public view returns (uint256[] memory) {
uint256 len = candidateNames.length;
// 在内存中开一个与候选人数量相同长度的 uint256 数组
uint256[] memory counts = new uint256[](len);
// 逐个读取字典里的票数，填到 counts 里
for (uint256 i = 0; i < len; i++) {
string memory name = candidateNames[i];
counts[i] = voteCount[name];
}
return counts;
}📑Day {04} in becoming a Solidity developer
✔️constructor函数用于初始化合约设定constructor() {}
✔️external函数仅允许外部合约与地址交互
✔️require(bool, string memory message)设置函数前提与错误返回消息
✔️所有合约的 Storage（状态变量）都是“零初始化”的
📑Day {05} in becoming a Solidity developer
✔️函数里return;可一键退出
✔️自定义modifier作为函数通用修饰符
✔️constructor (){}+msg.sender+modifier xxx(){}实现管理员权限功能
// Whoever deployed this contract becomes the owner
constructor() {
owner = msg.sender; //a global variable that tells us who is calling the constructor function
}
// Modifier for owner-only functions
modifier onlyOwner() {
require(msg.sender == owner, "Access denied: Only the owner can perform this action");
_;//配了修饰符onlyOwner的函数将在这里执行
}❓Logic advance: When approveWithdrawal, how make sure sum of withdrawalAllowances <= treasureAmount so that everyone can withdrawal at least what was allocated?
📑Day {06} in becoming a Solidity developer
✔️payable allows function to receive Ether
✔️msg.value holds the amount of Ether (in wei) that the user sent in
✔️mapping(address => bool)实现账户注册
🐞有一个BUG，视频代码里bankManager是没有注册的，应当在constructor里面声明
constructor(){
...
registeredMembers[msg.sender] = true;//register bankManager
...
}📑Day {07} in becoming a Solidity developer
✔️nested mapping logic
✔️transfer() sytax and its gas limit on interacting with smart contracts
<address payable>.transfer(uint256 amount); //send given amount of Wei to Address
✔️common requirements: _amount > 0 _adress!= address(0)
🤔call() syntax
(bool success, ) = <address payable>.call{value: _amount}("");
e.g. payable(msg.sender)
address payable xxx
mapping(address => mapping(address => uint256)) public debts
debts[debtor][creditor] = amount;
//EXAMPLE
debts[0xA][0xB] = 1.5 ether;
//A owes B 1.5 ETH
📑Day {08} in becoming a Solidity developer
✔️constructor里面可以使用后面定义的函数
✔️查重字符串数组(因为 Solidity 不允许直接用 == 比较两个串，所以用哈希值代替)
✔️public string[]初始长度为0
✔️换算 1 ETH = 10^18 wei
📑Day {09} in becoming a Solidity developer
①纯血计算方程我用pure从小用到大
②牛顿算法估计平方根
③build two smart contracts that work together: high-level function call(address casting)/ low-level call(Encode and Decode bytes )
import "./ScientificCalculator.sol";//importing its source code
ScientificCalculator sci = ScientificCalculator(scientificCalculatorAddress);
uint256 result = sci.power(base, exponent);ABI stands for Application Binary Interface. Think of it as a contract’s "communication protocol" — it defines how data must be structured when one contract calls another.
When using high-level function calls (like otherContract.someFunction()), Solidity handles ABI encoding for you. But with low-level calls, you must do it manually.
📑Day {10} in becoming a Solidity developer
① struct xxx {}
② Declare and emit Events
③ indexed parameter makes it searchable in frontend(indexed <=3 per event)
④ creating a storage reference within a func
📑Day {11} in becoming a Solidity developer
① contract inheritance and use OpenZeppelin
② address(this).balance查询合约余额
③ npm-style package system
📑Day {12} in becoming a Solidity developer
① ERC-20: the 20th proposal in the Ethereum Request for Comments series
② 使用套娃方程，separation of logic
📑Day {13} in becoming a Solidity developer
① virtualmakes function overridable by child contract
② use if () { require(false, ""); } to deliberately set revert condition
③ after LOGICALLY-Changed override(), fall back to the original function using return super.funcName();
④ UX-friendly receive() external payable {function();} automatically calls func within
📑Day {14} Advanced
① An interface xxx {} in Solidity is basically a contract with only function definitions — no logic, no storage, no state variables.
② We use abstract contract xxx {} as foundations — they are not meant to be deployed directly.
③ state variable private means only functions within this contract can read or modify it.
④ Array.pop() to remove the last item,
storage作为mapping默认存储位置，函数内使用storage可以作用于直接修改storage里的东西
在函数内部address[] storage boxlist = userDepositBoxes[msg.sender];
boxlist只是指向userDepositBoxes这个mapping的函数局部别名（alias）函数执行完毕后就消失，不会影响变量本名
for (uint i = 0; i < boxlist.length; i++) {
if (boxlist[i] == boxAddress) {
boxlist[i] = boxlist[boxlist.length - 1];//用结尾的值覆盖
boxlist.pop();//删结尾的值
break;
}
}