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#Lin JianBin
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自我介绍 我是JAVA出身,但目前在新加坡从事ETL工作,想要探索新的方向。
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你认为你会完成本次残酷学习吗? 我必须完成。
学习了函数类型,并在remix上做了一些练习,以下是我的学习内容。
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.21;
contract HelloWeb3{
string public _string = "Hello Web3!";
uint256 public number = 5;
uint public count=1;
uint public balance = 0;
function add() internal {
number +=1;
}
function addView() external view returns(uint256 newmuber){
newmuber = number + 5;
}
function addPure(uint256 _number) external pure returns (uint256 new_number) {
new_number = _number + 1;
}
function addPublic() public {
count += 5;
}
function addExternal() external {
count += 5;
}
function addPrivate() private {
count += 5;
}
function addInternal() internal {
count += 5;
}
function deposit( ) internal {
balance -= 1;
}
function depositPayable() external payable {
balance += 3;
}
function depositBalance() external returns(uint balance) {
deposit();
balance = address(this).balance;
}
}
- 学习payable方法, 手动充值ETH。
2024.09.24 #今天学习了函数的输出,可以同时输出多种不同类型。下面是在remix中练习。
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.21;
contract function_practice{
uint256[3] array;
//test return mutiple results
function returnMutiple() public pure returns(uint256, bool, uint256[3] memory){
return (1,true, [uint256(1),2,4]);
}
//命名式返回
function returnMutiple2() public pure returns(uint256 _number, bool _bool, uint256[3] memory
_array){
_number = 3;
_bool = true;
_array = [uint256(1), 2, 3];
}
//命名式返回支持return
function returnMutiple3() public pure returns (uint256 _number, bool _bool, uint256[3] memory
_array){
return(1, false, [uint256(3), 4, 6]);
}
//解构式赋值
function readFromFuction() public pure returns(uint256 , bool, uint256[3] memory) {
uint256 _number;
bool _bool;
uint256[3] memory _array;
(_number,_bool, _array ) = returnMutiple();
return (_number, _bool, _array);
}
}
- 学习了变量的数据存储和作用域。以下是在remix上的练习。 // SPDX-License-Identifier: MIT pragma solidity ^0.8.21;
contract solidity_start5{ uint[] xMemory = new uint[] (5);
uint public _s = 3;
string private _string = "a";
bool private _bool = true;
function fCalldata(uint[] calldata _x) public pure returns(uint[] calldata){
//参数为calldata数组,不能被修改
// _x[0] = 0 //这样修改会报错
return(_x);
} function testStorage() public { //此处不能使用pure或view关键字,因为下面的_storage[0]会修改状态变量。 uint[] storage _storage = xMemory; _storage[0] = 3; }
function testStorage2() internal view {
uint[] memory _storage = xMemory;
_storage[2] = 4;
}
//修改state variable 的值。
function changeStateVariables() external {
_s = 5;
_string = "JB";
_bool = false;
}
//局部变量
function declareLocalVariable() external pure returns(uint256 ll) {
uint _x = 3;
uint _y = 6;
ll = _x + _y;
}
function globalVariable() public view returns(address, uint, bytes memory) {
address _address = msg.sender;
uint blockNum = block.number;
bytes memory data = msg.data;
return (_address, blockNum, data);
}
function weuint() external pure returns(uint) {
assert(1 wei == 1e0);
assert(1 wei == 1);
return 1 wei;
}
function guint() external pure returns(uint) {
assert(1 gwei == 1e9);
assert(1 gwei == 1000000000);
return 1 gwei;
}
function etherTest() external pure returns(uint) {
assert(1 ether == 1e18);
assert(1 ether == 1000000000000000000);
return 1 ether;
}
//时间单位
function secondUint() external pure returns(uint){
assert(1 seconds == 1);
return 1 seconds;
}
function minutesUint() external pure returns(uint){
assert(1 minutes == 60);
return 1 minutes;
}
function hoursUint() external pure returns(uint) {
assert(1 hours == 3600);
return 1 hours;
}
function daysUnit() external pure returns(uint) {
assert(1 days == 86400);
assert(1 days == 24 hours);
return 1 days;
}
function weeksUnit() external pure returns(uint) {
assert(1 weeks == 604800);
assert(1 weeks == 7 days);
return 1 weeks;
}
}
1.学习了数组的声明以及赋值方式。 2.学习了struct的声明以及4种赋值方式。和JAVA中的POJO 类很像。 3.如下是做的练习。 // SPDX-License-Identifier: MIT pragma solidity ^0.8.21; contract array_struct {
//结构体 struct Student{ uint256 id; uint256 score; }
// 初始一个student结构体
Student public student;
//固定长数组
uint[3] _array1;
//不固定数组
uint[] _array2;
//不固定数组
uint [] _array3 = new uint[](3);
//固定长数组
bytes1[2] _byte1;
//固定长数组
address[10] _address;
bytes array;
function memory_array() external pure {
uint[] memory _array4 = new uint[](3);
_array4[0] = 3;
_array4[1] = 4;
_array4[2] = 3;
}
function callG() public {
g([uint(3),3,5]);
}
function g(uint[3] memory _as) public returns (uint[] memory ) {
_array3 = _as;
_array3.push(3);
return _array3;
}
function initStudent1() external {
Student storage _student = student;
_student.id = 11;
_student.score = 100;
}
//直接引用strut。
function initStudent2() external {
student.id = 3;
student.score = 90;
}
//构造函数
function initStudent3() external {
student = Student(3,90);
}
//key-value形式
function initStudent4() external {
student = Student({id:3,score:40});
}
总结:对语法不熟悉,对数组修饰符之间的变量赋值影响理解不够深刻。
学习了mapping的映射。 // SPDX-License-Identifier: MIT pragma solidity ^0.8.21;
contract Map{
mapping (uint => address) public idAddress;
mapping (address => address) public swaPair;
// struct Student{
// uint256 id;
// uint256 score;
// }
mapping (address => address) public student;
function writeMap (uint _Key, address _Value) public {
idAddress[_Key] = _Value;
}
}
学习了变量初始值的,以及如何使用delete方法恢复变量的初始值。 // SPDX-License-Identifier: MIT pragma solidity ^0.8.21; contract initValue {
bool public _bool;
string public _string;
int public _int;
uint public _uint;
address public _address;
enum Action {Buy, Hold, Sell}
Action public _enum;
struct Student {
uint score;
uint id;
}
Student private _tom;
function fi() internal {}
function gi() external {}
uint256 [5] _static;
uint [] _dynamic;
function test_bool() public {
_bool = true;
}
function call() external returns(bool ) {
this.test_bool();
return _bool;
}
function call_delete() external {
_bool = this.call();
delete _bool;
}
}
学习了常量constant和不可变量 immutable // SPDX-License-Identifier: MIT pragma solidity ^0.8.21; contract test_Constant{ uint public constant CONSTANT_NUM = 10; string public constant CONSTANT_STRING= "ini"; bool public constant live = true; bytes public constant CONSTANT_BYTES="WTF"; address public constant CONSTANT_ADDRESS=address(1);
uint public immutable IMMUTABLE_NUM = 10000;
address public immutable IMMUTABLE_ADDRESS;
uint public immutable IMMUTABLE_BLOCK;
uint public immutable IMMUTABLE_TEST;
constructor(){
IMMUTABLE_ADDRESS = address(this);
IMMUTABLE_NUM = 9999;
IMMUTABLE_TEST = test();
}
function test() public pure returns(uint return_test) {
return_test = 9;
}
}
学习了循环。 // SPDX-License-Identifier: MIT pragma solidity ^0.8.21;
contract control_test{ uint constant phone_number = 88996958;
//if-else
function control(uint256 number) public pure returns(bool bo) {
if (number == 0) {
return true;
} else if (number == 4){
bo ==false;
} else bo == false;
}
//for loop
function for_test() public pure returns(uint result) {
uint sum = 0;
for (uint i = 0; i<=100; i++){
sum += i;
}
return sum;
}
//while
function while_test() public pure returns(uint sum_) {
uint i = 0;
uint sum = 0;
while (i < 100) {
sum += i;
i++;
}
sum_ = sum;
}
//do while loop
function do_while_test() public pure returns (uint do_while_result){
uint sum = 0;
uint i = 0;
do {
sum += i;
} while(i<100);
return sum;
}
function ternary_test(uint x, uint y) public pure returns(uint){
return x > y ? x:y;
}
//插入排序
function sort_test(uint[] memory array) public pure returns(uint256[] memory ) {
for (uint i =1; i < 100; i++){
uint temp = array[i];
uint j = i;
while (j > 0 && array[i] > array[j-1]) {
array[i] = array[j-1];
j--;
}
array[j] = temp;
}
return array;
}
function test_insert_sort() public pure {
uint256[] memory array;
array[0] = 9;
array[1] = 6;
array[2] = 7;
array[3] = 9;
array[4] = 0;
sort_test(array);
}
- 解决了上次遇到的局部变量中用memory声明的数组不能传入参数的问题。 //插入排序 function sort_test(uint[] memory array) public pure returns(uint[] memory ) { for (uint i =1; i < array.length;i++){ uint temp = array[i]; uint j = i; while ((j > 0) && (temp < array[j-1])) { array[j] = array[j-1]; j--; } array[j] = temp; } return array; } function test_insert_sort() public pure returns(uint[] memory) { uint[] memory array = new uint; array[0] = 9; array[1] = 6; array[2] = 7; array[3] = 9; array[4] = 0; sort_test(array); return array; } 2. 练习了构造方法和modifier 修饰关键字 // SPDX-License-Identifier: MIT pragma solidity ^0.8.21;
contract test_contructor{ address public _address;
constructor (address inital_address) {
_address = inital_address;
}
modifier onlyOwner {
require(msg.sender == _address);// f检查调用者是否为owner
_; //if it is true, then continue
}
function changeOwner(address change_address) external onlyOwner{
_address = change_address;
}
}
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了解了什么是事件以及如何定义。并在remix上进行测试。 // SPDX-License-Identifier: MIT pragma solidity ^0.8.21; contract test_event{
mapping(address => uint256) public _balances; event Transfer(address indexed from, address indexed to, uint256 value);
function transfer( address from, address to, uint256 amount ) external { _balances[from] = 10000000; // 给转账地址一些初始代币
_balances[from] -= amount; // from地址减去转账数量 _balances[to] += amount; // to地址加上转账数量
// 释放事件 emit Transfer(from, to, amount); } }
- 了解事件的使用方式。
- 学习事件的使用场景。 https://www.youtube.com/watch?v=H4s4Rf3E-EI&list=PL-edkZcvwC5a7qIaHG4Rsj6DkOM3YH3eT&index=12
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学习了继承以及多重继承
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学习了modifier的继承 // SPDX-License-Identifier: MIT pragma solidity ^0.8.21; contract inheritance_GrandFather{ event Log(string msg);
//define three functions function hip() public virtual{ emit Log("Grandfather"); }
function pop() public virtual { emit Log("Grandfather"); }
function grandfather() public virtual { emit Log("Grandfather"); } }
contract father is inheritance_GrandFather{
function hip() public virtual override {
emit Log("father");
}
function pop() public virtual override {
emit Log("father");
}
function grandfather() public virtual override {
emit Log("father");
}
}
contract child is inheritance_GrandFather, father{ function hip() public virtual override(inheritance_GrandFather, father) { emit Log("child"); }
function pop() public virtual override(inheritance_GrandFather, father) {
emit Log("child");
}
function grandfather() public virtual override(inheritance_GrandFather, father) {
emit Log("child");
}
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学习了构造函数继承
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学习了钻石继承 // SPDX-License-Identifier: MIT pragma solidity ^0.8.21; abstract contract A { uint256 public a; uint256 public b;
constructor(uint256 _a,uint256 _b) { a = _a ; b = _b; } }
contract B is A{ constructor(uint256 a, uint256 b) A(a * a, b * b){
}
}
// SPDX-License-Identifier: MIT pragma solidity ^0.8.21; contract God{ event Log(string message);
function foo() public virtual {
emit Log("God. foo called");
}
function bar() public virtual {
emit Log("God. bar called");
}
}
contract Adam is God{ function foo() public virtual override { emit Log("Adam.foo called"); super.foo(); }
function bar() public virtual override {
emit Log("Adam.bar called");
super.bar();
}
}
contract Eve is God {
function foo() public virtual override {
emit Log("Eve. foo called");
super.foo();
}
function bar() public virtual override {
emit Log("Eve. bar called");
super.bar();
}
}
contract People is Adam, Eve{
function foo() public override(Adam, Eve) {
super.foo();
}
function bar() public override (Adam, Eve) {
super.bar();
}
}