contract BasicToken is ERC20Basic {
using SafeMath for uint256;
mapping(address => uint256) balances;
uint256 totalSupply_;
/**
* @ token总量
*/
function totalSupply() public view returns (uint256) {
return totalSupply_;
}
/**
* @dev 转账
* @param _to 转给谁
* @param _value 转多少.
*/
function transfer(address _to, uint256 _value) public returns (bool) {
require(_to != address(0));//不能自己转自己
require(_value <= balances[msg.sender]);//转账金额小于等于账户余额
balances[msg.sender] = balances[msg.sender].sub(_value);//转出账户减去金额
balances[_to] = balances[_to].add(_value);//收入账户添加金额
emit Transfer(msg.sender, _to, _value);//发送时间通知
return true;
}
/**
* @查询账户的余额
* @param _owner 账户地址
* @return An uint256 返回余额
*/
function balanceOf(address _owner) public view returns (uint256) {
return balances[_owner];
}
}
通过这个源码可以看到、基本的token实现、主要是实现了，查询余额、转账、转账事件、token总量等方法。
需要注意的地方是uint256进行运算的时候，防止被黑客攻击，一定用safeMath来处理计算。
对于改变区块链状态的方法，一定要多重校验。
通过require方法来实现。
参考意见：
- 只要涉及到计算，一定要用safeMath
- 代码一定要反复测试！
- 代码一定要有经验的同事review！
- 必要时，要请专门做代码审计的公司来 测试代码
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