pragma solidity ^0.4.24;

//标准ERC20Token接口
contract ERC20Token{
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);

}
//东大门EastToken
contract EastToken is ERC20Token {
string public name; //名称
string public symbol; //token简称
uint8 public decimals; //返回token使用的小数点后几位

mapping (address => uint256) public balances;
mapping (address => mapping (address => uint256)) public allowed;
//构造函数
constructor(uint256 _initialAmount, string _tokenName, uint8 _decimals, string _tokenSymbol) public {
    totalSupply = _initialAmount * 10 ** uint256(_decimals);        // 设置初始总量
    balances[msg.sender] = totalSupply;                              //初始token数量给予消息发送者，即合约的创建者
    name = _tokenName;
    decimals = _decimals;
    symbol = _tokenSymbol;
}
//调用者转账给to地址
function transfer(address _to, uint256 _value) public returns (bool success) {
    //默认totalSupply不会超过最大值 (2^256 - 1)，避免溢出的异常
    require(balances[msg.sender] >= _value && balances[_to] + _value > balances[_to]);
    require(_to != 0x0);                             //不能转空地址
    balances[msg.sender] -= _value;                  //从消息发送者账户中减去token数量_value
    balances[_to] += _value;                         //往接收账户增加token数量_value
    emit Transfer(msg.sender, _to, _value);          //触发转币交易事件
    return true;
}
//第三方调用转账
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
    require(balances[_from] >= _value && allowed[_from][msg.sender] >= _value);
    balances[_to] += _value;                          //接收账户增加token数量_value
    balances[_from] -= _value;                        //支出账户_from减去token数量_value
    allowed[_from][msg.sender] -= _value;             //消息发送者可以从账户_from中转出的数量减少_value
    emit Transfer(_from, _to, _value);                //触发转币交易事件
    return true;
}
//查询_owner的余额
function balanceOf(address _owner) public constant returns (uint256 balance) {
    return balances[_owner];
}
//授权_spender在spender中花费_value
function approve(address _spender, uint256 _value) public returns (bool success){
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
}
//允许_spender从_owner中转出的token数
function allowance(address _owner, address _spender) public constant returns (uint256 remaining) {
    return allowed[_owner][_spender];
}

//批转10000
}