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@chnejohnson
Created February 2, 2021 13:19
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pragma solidity ^0.7.0;
// 這是一個叫做 Token 的合約
contract Token {
// 貨幣的名稱叫做...
string public name = "My Awesome Token";
// 貨幣的代號是...
string public symbol = "MAT";
// 貨幣的總供給量
uint256 public totalSupply = 1000000;
// 此合約擁有者的地址
address public owner;
// 將不同地址映射到不同的貨幣持有量
mapping(address => uint256) balances;
// 當合約一部屬上鏈,就執行 constructor 裡的程式,謹此一次,此後就不會再執行
constructor() {
balances[msg.sender] = totalSupply;
owner = msg.sender;
}
// 此合約提供的第一個 function,貨幣轉移,填入一個地址和數量即可執行
function transfer(address to, uint256 amount) external {
require(balances[msg.sender] >= amount, "Not enough tokens");
balances[msg.sender] -= amount;
balances[to] += amount;
}
// 此合約第二個 function,查詢持有的數量,填入一個地址就會回傳該地址擁有的貨幣持有量
function balanceOf(address account) external view returns (uint256) {
return balances[account];
}
}
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