pragma solidity ^0.4.16;
contract BBCCToken{
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 BBCC is BBCCToken {

string public name; //名称，例如" BBCCToken, BBCC "
uint8 public decimals; //返回token使用的小数点后几位。比如如果设置为3，就是支持0.001表示.

string public symbol; //24 token简称,like BBCC

function BBCC(uint256 _initialAmount, string _tokenName, uint8 _decimalUnits, string _tokenSymbol) public {

totalSupply = _initialAmount * 10 ** uint256(_decimalUnits);// 设置初始总量

balances[msg.sender] = totalSupply; // 初始token数量给予消息发送者，因为是构造函数，所以这里也是合约的创建者

name = _tokenName;
decimals = _decimalUnits;
symbol = _tokenSymbol;
}

function transfer(address _to, uint256 _value) public returns (bool success) {

//默认totalSupply 不会超过最大值 (2^256 - 1).
//如果随着时间的推移将会有新的token生成，则可以用下面这句避免溢出的异常
require(balances[msg.sender] >= _value && balances[_to] + _value >balances[_to]);

require(_to != 0x0);
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
Transfer(msg.sender, _to, _value);//触发转币交易事件
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;//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

Transfer(_from, _to, _value);//触发转币交易事件
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;
Approval(msg.sender, _spender, _value);
return true;
}

function allowance(address _owner, address _spender) public constant
returns (uint256 remaining) {
return allowed[_owner][_spender];//允许_spender从_owner中转出的token数

}
mapping (address => uint256) balances;
mapping (address => mapping (address => uint256)) allowed;
}