ethereum(以太坊)(十二)--应用(一)__集资(构造函数/映射)

pragma solidity ^0.4.4;

contract funder{

    //0xca35b7d915458ef540ade6068dfe2f44e8fa733c

    //0x14723a09acff6d2a60dcdf7aa4aff308fddc160c :10

    //0x583031d1113ad414f02576bd6afabfb302140225 :20

    struct Funder{

        address addr;

        uint amount;

    }

    struct Campaign{

        address beneficiary; //受益人

        uint fundingGoal; //集资目标

        uint numFunders;  //出资人数

        uint mount;       //已集资数

        mapping(uint => Funder) Funders; //按照索引存储出资人信息

    }

    uint numCampaigns;

    mapping(uint => Campaign) public Campaigns;  //按照索引存储每个受益人的状态

    //向指定受益人出资一定数量的钱

    //function newCampaign(address beneficiary,uint goal) public returns(uint campaignID){

    //function newCampaign(address beneficiary,uint goal) public{ //DeclarationError: Undeclared identifier__campaignID

    function newCampaign(address beneficiary,uint goal) public{

        //var campaignID = numCampaigns++;

        //Campaigns[campaignID] = Campaign(beneficiary,goal,0,0);

        Campaigns[numCampaigns] = Campaign(beneficiary,goal,0,0);

        numCampaigns ++;

    }

    function contribute(uint campaignID) public payable{

        Campaign storage c = Campaigns[campaignID];  //每个受益人的状态

        c.Funders[c.numFunders++] = Funder({addr:msg.sender,amount:msg.value});

        //Funder({addr:msg.sender,amount:msg.value}) 当前转账人的地址,和转账金额

        //c.numFunders++ 统计向当前受益人转账的人数

        // 0 => 转账地址

        c.mount += msg.value; //当前受益人的总受益

        c.beneficiary.transfer(msg.value);//向受益人的地址转入ethtereum

    }

    function checkGoalReached(uint campaignID) public constant returns(bool reached){

        Campaign storage c = Campaigns[campaignID];

        if(c.mount < c.fundingGoal){

            return false;

        }

        return true;

    }

}

遇到的问题:

1.受益人可以相同
2.struct+mapping:根据索引存储大量结构体