# Hello World

步驟提示

truffle init # 1. 初始化
# 2. 更改檔案內容
truffle compile #3. 寫完智能合約後編譯
truffle migrate #4. 部屬

contracts/HelloWorld.sol

// SPDX-License-Identifier: MIT
// compiler version must be greater than or equal to 0.8.10 and less than 0.9.0
pragma solidity ^0.8.10;

contract HelloWorld {
    string public greet = "Hello World!";
}

migrations/2_depoly_hello_world.js // 要加上序數，否則migrate 無法辨認

const HelloWorld = artifacts.require("HelloWorld.sol");

module.exports = function (deployer) {
  deployer.deploy(HelloWorld);
};

truffle-config.js

module.exports = {
  networks: {
    development: {
     host: "127.0.0.1",     // Localhost (default: none)
     port: 7545,            // Standard Ethereum port (default: none)
     network_id: "*",       // Any network (default: none)
    },
  },

  compilers: {
    solc: {
      version: "0.8.10",    // Fetch exact version from solc-bin (default: truffle's version)
       optimizer: {
         enabled: true,
         runs: 200
       },
    }
  },
};

貼完上述程式就可以執行
`truffle compile # 編譯`
`truffle migrate # 部屬`
truffle migrate 後結果