以太坊发币全流程有哪些？

也许你经常看到ERC20和代币一同出现， ERC20是以太坊定义的一个代币标准。要求我们在实现代币的时候必须要遵守的协议，如指定代币名称、总量、实现代币交易函数等，只有支持了协议才能被以太坊钱包支持。其接口如下：

contract ERC20Interface { string public constant name = "Token Name"; string public constant symbol = "SYM"; uint8 public constant decimals = 18; // 18 is the most common number of decimal places function totalSupply() public constant returns (uint); function balanceOf(address tokenOwner) public constant returns (uint balance); function allowance(address tokenOwner, address spender) public constant returns (uint remaining); function transfer(address to, uint tokens) public returns (bool success); function approve(address spender, uint tokens) public returns (bool success); function transferFrom(address from, address to, uint tokens) public returns (bool success); event Transfer(address indexed from, address indexed to, uint tokens); event Approval(address indexed tokenOwner, address indexed spender, uint tokens);}

简单说明一下：

name ： 代币名称symbol： 代币符号decimals： 代币小数点位数，代币的最小单位， 18表示我们可以拥有 .0000000000000000001单位个代币。totalSupply() : 发行代币总量。balanceOf(): 查看对应账号的代币余额。transfer(): 实现代币交易，用于给用户发送代币（从我们的账户里）。transferFrom(): 实现代币用户之间的交易。allowance(): 控制代币的交易，如可交易账号及资产。approve(): 允许用户可花费的代币数。

编写代币合约代码

代币合约代码：

pragma solidity ^0.4.16;interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) public; }contract TokenERC20 { string public name; string public symbol; uint8 public decimals = 18; // 18 是建议的默认值 uint256 public totalSupply; mapping (address => uint256) public balanceOf; // mapping (address => mapping (address => uint256)) public allowance; event Transfer(address indexed from, address indexed to, uint256 value); event Burn(address indexed from, uint256 value); function TokenERC20(uint256 initialSupply, string tokenName, string tokenSymbol) public { totalSupply = initialSupply * 10 ** uint256(decimals); balanceOf[msg.sender] = totalSupply; name = tokenName; symbol = tokenSymbol; } function _transfer(address _from, address _to, uint _value) internal { require(_to != 0x0); require(balanceOf[_from] >= _value); require(balanceOf[_to] + _value > balanceOf[_to]); uint previousBalances = balanceOf[_from] + balanceOf[_to]; balanceOf[_from] -= _value; balanceOf[_to] += _value; Transfer(_from, _to, _value); assert(balanceOf[_from] + balanceOf[_to] == previousBalances); } function transfer(address _to, uint256 _value) public { _transfer(msg.sender, _to, _value); } function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) { require(_value <= allowance[_from][msg.sender]); // Check allowance allowance[_from][msg.sender] -= _value; _transfer(_from, _to, _value); return true; } function approve(address _spender, uint256 _value) public returns (bool success) { allowance[msg.sender][_spender] = _value; return true; } function approveAndCall(address _spender, uint256 _value, bytes _extraData) public returns (bool success) { tokenRecipient spender = tokenRecipient(_spender); if (approve(_spender, _value)) { spender.receiveApproval(msg.sender, _value, this, _extraData); return true; } } function burn(uint256 _value) public returns (bool success) { require(balanceOf[msg.sender] >= _value); balanceOf[msg.sender] -= _value; totalSupply -= _value; Burn(msg.sender, _value); return true; } function burnFrom(address _from, uint256 _value) public returns (bool success) { require(balanceOf[_from] >= _value); require(_value <= allowance[_from][msg.sender]); balanceOf[_from] -= _value; allowance[_from][msg.sender] -= _value; totalSupply -= _value; Burn(_from, _value); return true; }}

部署

在开发测试智能合约时，MetaMask和Remix Solidity IDE是两个非常好用的工具，用来完成部署。

安装和配置MetaMask请参考开发、部署第一个去中心化应用，选择了以太坊的测试网络Ropsten，如果你没有余额请点击购买buy，进入的网站可以送一些测试以太币给你，配置好之后，界面应该如下：

浏览器打开Remix Solidity IDE，复制以上源码粘贴上，在右侧选项参考如图的设置：注意Environment和Account和MetaMask保持一致，然后选择合约TokenERC20，填入你想要的发行量，名称及代号，就可以创建合约了。这时MetaMask会弹出一个交易确认框，点SUBMIT。待合约部署交易确认之后，点击交易详情如下图，复制合约地址（下图中红色框内）。打开Metamask界面，切换到TOKENS，点添加合约，出现如下对话框：填入刚刚复制的地址，点ADD，这时你就可以看到你创建的代币了，如图：你已经完成了代币的创建和部署(正式网络和测试网络部署方法一样)，可以在Etherscan查询到我们刚刚部署的代币，如文章开头的图片，代币发行量为10000，单位为SB。