Skip to content

Latest commit

 

History

History
100 lines (74 loc) · 5.39 KB

ChenBingWei1201.md

File metadata and controls

100 lines (74 loc) · 5.39 KB
Raw
timezone
Asia/Shanghai

YourName

  1. 自我介绍 大家好我叫Chen Bing Wei，我以前只有學習過往佔前後都開發，從未接觸solidity與smart contract這類的東西，但今年因緣際會下修了一門叫分散式金融導論的課，助教教的非常好，讓我對這個領域充滿極大的興趣，或許未來可以做跨領域的結合，結合網路服務，金融科技，與機器學習等現在所學的知識，創造出能對人類有所貢獻的東西，因此想藉由這次機會挑戰自己，參加此次活動逼迫自己學習。

  2. 你认为你会完成本次残酷学习吗？ 會

Notes

2024.09.23

WTF is Solidity?

  • Solidity is a programming language used for creating smart contracts on the Ethereum Virtual Machine (EVM).
  • Solidity has two characteristics:
    1. Object-oriented: After learning it, you can use it to make money by finding the right projects.
    2. Advanced: If you can write smart contract in Solidity, you are the first class citizen of Ethereum.

Development tool: Remix

Remix is an smart contract development IDE (Integrated Development Environment) recommended by Ethereum official.

  • Advantages
    1. Suitable for Beginners: It allows for quick deployment and testing of smart contracts in the browser, without needing to install any programs on your local machine.
    2. Gas Estimation Issue: It will estimation the cost of gas on every functions and display behind them, which can remind developers that wheter functions should be optimized or not.
  • Disadvantages
    1. Limited to Browser: Since Remix is a browser-based IDE, it can be less stable or responsive compared to desktop IDEs like VSCode, especially when working with larger projects or multiple open files.
    2. Collaboration Limitations: Remix doesn’t have built-in features for real-time collaboration or version control like Git, making it more difficult to work in teams.

Website: remix.ethereum.org

The first Solidity program

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;
contract HelloWeb3 {
    string public _string = "Hello Web3!";
}
  1. The first line is a comment, which denotes the software license (license identifier) used by the program. We are using the MIT license. If you do not indicate the license used, the program can compile successfully but will report an warning during compilation. Solidity's comments are denoted with "//", followed by the content of the comment (which will not be run by the program). Details can be found in the SPDX-License documentation.
  2. The second line declares the Solidity version used by the source file, because the syntax of different versions is different. This line of code means that the source file will not allow compilation by compilers version lower than v0.8.4 and not higher than v0.9.0 [0.8.4, 0.9.0).
  • There is slight difference among distinct versions: 0.4.22 -> constructor, 0.8.0 -> safeMath
  • Include the pragma version in every file: Locking the version is preferable, except for libraries.
  • Pattern: pragma solidity x.y.z: e.g. pragma solidity ^0.8.3 : [0.8.3, 0.9.0) or pragma solidity >=0.8.3 <0.8.7
  1. Lines 3 and 4 are the main body of the smart contract. Line 3 creates a contract with the name HelloWeb3. Line 4 is the content of the contract. Here, we created a string variable called _string and assign "Hello Web3!" as value to it.

Summary

In the first day, I learned what is Solidity, Remix IDE, and completed our first Solidity program - HelloWeb3.

2024.09.24

Variable Types

Solidity is statically-type language, which means the type of each variable needs to be specified in code at compile time.

  1. Value Type： This include boolean, integer, etc. These variables directly pass values when assigned.
  2. Reference Type：including arrays and structures. These variables take up more space, directly pass addresses (similar to pointers) when assigned, and can be modified with multiple variable names.
  3. Mapping Type: hash tables in Solidity.

1. Value Type

Type Example Byte Default Value
Boolean true / false 1 Byte False
Usigned Integer uint128, uint256 uint256 - 32 bytes 0
Integer int128, int256 int256 - 32 bytes 0
address* / adress payable* address public _address = 0x5C69...5aA6 20 bytes address(0)
Fixed-Sized bytes array bytes32 public _byte32 = "MiniSolidity"; bytes1 public _byte = _byte32[0]; bytes32 - 32 bytes bytes32(0)
Enumeration enum ActionSet { Buy, Hold, Sell } uint 0, 1, 2 -

*address payable: Same as address, but with the additional members transfer and send to allow ETH transfers.

*There are two types of accounts: EOA & CA

  • EOA(Externally Owned Account): For example, Wallet Address
  • CA(Contract Account): For example, Simple Bank Contract

2. Reference Type

Type Example
Array uint256[], string, bytes (Dynamic Size Bytes Array)
Struct struct Demo {uint256 x, uint256 y}

3. Mapping Type

Type Example
Mapping mapping(address=>uint256), mapping(address addr=>uint), mapping(address addr=>uint balance)