QZCrowdsale.sol

pragma solidity ^0.4.21;

contract QZCrowdsale {
    address public owner;
    uint public fundingGoal;
    uint public amountRaised;
    uint public deadline;
    address[] investors;
    mapping(address => uint256) public balanceOf;
    bool public fundingGoalReached;
    bool public crowdsaleClosed;

    event CrowdsaleClosed(uint amountRaised);
    event FundTransfer(address to, uint amount);

    /* data structure to hold information about campaign contributors */

    /*  at initialization, setup the owner */
    function QZCrowdsale(
        uint fundingGoalInEthers,
        uint durationInMinutes
    ) public {
        owner = msg.sender;
        fundingGoal = fundingGoalInEthers * 1 ether;
        deadline = now + durationInMinutes * 1 minutes;
        amountRaised = 0;
        fundingGoalReached = false;
        crowdsaleClosed = false;
    }

    function numberOfInvestors() view public returns (uint) {
        return investors.length;
    }

    function investorAddress(uint i) view public returns (address) {
        return investors[i];
    }

    /* The function without name is the default function that is called whenever anyone sends funds to a contract */
    function () payable public {
        require(!crowdsaleClosed);
        require(now < deadline);
        uint amount = msg.value;
        balanceOf[msg.sender] += amount;
        investors.push(msg.sender);
        amountRaised += amount;
        if (amountRaised >= fundingGoal) {
            fundingGoalReached = true;
            crowdsaleClosed = true;
            emit CrowdsaleClosed(amountRaised);
        }
    }

    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

    modifier onlyWhenCrowdsaleIsClosed() {
        require(crowdsaleClosed == true);
        _;
    }

    /* checks if the goal or time limit has been reached and ends the campaign */
    function checkForClosureConditions() onlyOwner public {
        if (now >= deadline) {
            crowdsaleClosed = true;
            emit CrowdsaleClosed(amountRaised);
        } else if (amountRaised >= fundingGoal) {
            fundingGoalReached = true;
            crowdsaleClosed = true;
            emit CrowdsaleClosed(amountRaised);
        }
    }

    function closeCrowdsaleManually() onlyOwner public {
        crowdsaleClosed = true;
        emit CrowdsaleClosed(amountRaised);
    }

    function safeWithdrawal() onlyWhenCrowdsaleIsClosed onlyOwner public {
        require(owner.send(amountRaised));
    }
}