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本文主要介紹如何編寫(xiě)以太坊ERC20的代幣，并且在以太坊測(cè)試網(wǎng)絡(luò)部署。

為什么需要先在測(cè)試網(wǎng)絡(luò)進(jìn)行測(cè)試合約？因?yàn)槿绻苯影押霞s部署到主網(wǎng)，測(cè)試不充分的情況下消耗的是真實(shí)的ETH，而測(cè)試環(huán)境ETH都是免費(fèi)的。

1.以太坊ERC20代幣規(guī)范

官方ERC20規(guī)范文檔：https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md

首先需要編寫(xiě)代幣智能合約，必須遵從ERC20標(biāo)準(zhǔn)接口：


contract Token{
    uint256 public totalSupply; //代幣發(fā)行總數(shù)

   //查詢(xún)某個(gè)地址下代幣數(shù)量
    function balanceOf(address _owner) public constant returns (uint256 balance); 
   //向其他地址發(fā)送代幣
    function transfer(address _to, uint256 _value) public returns (bool success);

   //從一個(gè)地址提取代幣到另外一個(gè)地址
    function transferFrom(address _from, address _to, uint256 _value) public returns
    (bool success);

   //授權(quán)允許從一個(gè)地址到另外一個(gè)地址轉(zhuǎn)代幣
    function approve(address _spender, uint256 _value) public returns (bool success);

  //查詢(xún)某個(gè)地址允許從另外一個(gè)地址轉(zhuǎn)走代幣的數(shù)量
    function allowance(address _owner, address _spender) public constant returns
    (uint256 remaining);

     //當(dāng)向其他地址發(fā)送代幣觸發(fā) 
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    //當(dāng)從一個(gè)代碼提取代幣到另外一個(gè)地址時(shí)觸發(fā)
    event Approval(address indexed _owner, address indexed _spender, uint256
    _value);
}

實(shí)現(xiàn)這些接口：


contract Token{
    uint256 public totalSupply;

    function balanceOf(address _owner) public constant returns (uint256 balance);
    function transfer(address _to, uint256 _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns
    (bool success);

    function approve(address _spender, uint256 _value) public returns (bool success);

    function allowance(address _owner, address _spender) public constant returns
    (uint256 remaining);

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256
    _value);
}

contract TokenTemplate is Token {

    string public name;//代幣名稱(chēng)，如BitShare
    uint8 public decimals;//代幣精度，即小數(shù)點(diǎn)后幾位
    string public symbol;//代幣簡(jiǎn)稱(chēng)，如bts
    address owner;

    mapping (address => uint256) balances;
    mapping (address => mapping (address => uint256)) allowed;

   //如果希望合約能夠正常接受eth
    function () payable{
        
    }

   //創(chuàng)建合約時(shí)，初始化總代幣數(shù)，名稱(chēng)等相關(guān)信息
    function TokenTemplate(uint256 _initialAmount, string _tokenName, uint8 _decimalUnits, string _tokenSymbol) public {
        totalSupply = _initialAmount * 10 ** uint256(_decimalUnits);
        balances[msg.sender] = totalSupply;

        name = _tokenName;
        decimals = _decimalUnits;
        symbol = _tokenSymbol;

        owner = msg.sender;
    }

    function transfer(address _to, uint256 _value) public returns (bool success) {
        require(balances[msg.sender] >= _value && balances[_to] + _value > balances[_to]);
        require(_to != 0x0);
        balances[msg.sender] -= _value;
        balances[_to] += _value;
        emit Transfer(msg.sender, _to, _value);
        return true;
    }


    function transferFrom(address _from, address _to, uint256 _value) public returns
    (bool success) {
        require(balances[_from] >= _value && allowed[_from][msg.sender] >= _value);
        balances[_to] += _value;
        balances[_from] -= _value;
        allowed[_from][msg.sender] -= _value;
        emit Transfer(_from, _to, _value);
        return true;
    }
    function balanceOf(address _owner) public constant returns (uint256 balance) {
        return balances[_owner];
    }


    function approve(address _spender, uint256 _value) public returns (bool success)
    {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    function allowance(address _owner, address _spender) public constant returns (uint256 remaining) {
        return allowed[_owner][_spender];
    }

    function destory(){
        if (owner == msg.sender) {
            selfdestruct(owner);
        }
    }

}