1-2.md

第1讲(Solidity結構)

// SPDX-License-Identifier: MIT

代表軟體授權協議

pragma solidity ^0.8.21;

代表版本需 >= 0.8.21 且 < 0.9.0

第2讲(Solidity variable type)

1. Value type: Boolean, Integer
2. Reference type: Array, Struct
3. Mappping type: Key-value pair

Boolean operator

1. ! => not
2. && => and
3. || => or
4. == => equal
5. != => not equal

Integer

1. int (Including negative number)
2. uint (Only positive number)
3. uint256 (256 bytes positive number) => 0~2^256-1

Note: uint = uint256

Address (20 bytes)

1. payable address: 相比address, 多了transfer與send

String

1. Fixed length string(Value type) 最多32bytes

bytes32 public _byte32 = "MiniSolidity";

若轉成16進制 => 0x4d696e69536f6c69646974790000000000000000000000000000000000000000

bytes1 public _byte = _byte32[0]; 

_byte為_byte32的第一個字節: 0x4d

2. Non Fixed length string(Reference type)