'''
pragma solidity ^0.4.2;
contract token { function transfer(address receiver, uint amount){ } }
contract Crowdsale {
address public beneficiary;//受益人
uint public fundingGoal; //目标金额
uint public amountRaised;
uint public deadline; //截止时间
uint public price; //每个价格
token public tokenReward;
mapping(address => uint256) public balanceOf;//每个地址的众筹数目,map类型
bool fundingGoalReached = false;
event GoalReached(address beneficiary, uint amountRaised); //事件,众筹目标达到
event FundTransfer(address backer, uint amount, bool isContribution);//事件,发送资金发送时候
bool crowdsaleClosed = false;
/* data structure to hold information about campaign contributors */
/* at initialization, setup the owner */
function Crowdsale(
address ifSuccessfulSendTo, //众筹成功后,转移目标地址
uint fundingGoalInEthers, //投资目标
uint durationInMinutes, //持续时间
uint etherCostOfEachToken, //每个的最小投资额度
token addressOfTokenUsedAsReward //当前受益地址
) {
beneficiary = ifSuccessfulSendTo;
fundingGoal = fundingGoalInEthers * 1 ether;
deadline = now + durationInMinutes * 1 minutes;
price = etherCostOfEachToken * 1 ether;
tokenReward = token(addressOfTokenUsedAsReward); //受益地址,数量合约
}
/* The function without name is the default function that is called whenever anyone sends funds to a contract */
function () payable {//合约默认执行函数,在有人给合约地址发送资金时执行
if (crowdsaleClosed) throw;//众筹关闭时,抛出异常
uint amount = msg.value;
balanceOf[msg.sender] = amount; //计入统计,发送者发送的数量
amountRaised += amount; //累计收到的金额
tokenReward.transfer(msg.sender, amount / price);
FundTransfer(msg.sender, amount, true); //发送资金变动事件通知
}
// modifier可以方便的验证输入信息
modifier afterDeadline() { if (now >= deadline) _; }//modifier 修饰符,函数启动前执行。_表示函数体占位符,此处表示afterDeadline修饰的函数本体。
//检查是否众筹成功,达到目标金额
/* checks if the goal or time limit has been reached and ends the campaign */
function checkGoalReached() afterDeadline {
if (amountRaised >= fundingGoal){ //收集总金额大于目标金额
fundingGoalReached = true; //修改众筹金额达成标志为成功
GoalReached(beneficiary, amountRaised); //触发金额达到事件
}
crowdsaleClosed = true; //众筹标识关闭
}
//安全撤出, 有afterDeadline的话,只有到众筹结束时间才可以执行
function safeWithdrawal() afterDeadline {
if (!fundingGoalReached) {//如果众筹众筹金额未达成
uint amount = balanceOf[msg.sender];
balanceOf[msg.sender] = 0;
if (amount > 0) {
if (msg.sender.send(amount)) {//金额退回资金发送者
FundTransfer(msg.sender, amount, false);
} else {
balanceOf[msg.sender] = amount;//记录放入balanceOfmap里面
}
}
}
if (fundingGoalReached && beneficiary == msg.sender) {//众筹金额达成,且发送者(查询者)是受益人
if (beneficiary.send(amountRaised)) {//金额发送给受益人
FundTransfer(beneficiary, amountRaised, false);
} else {
//If we fail to send the funds to beneficiary, unlock funders balance
fundingGoalReached = false; ////众筹金额未达成
}
}
}
}
'''
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