基于以太坊的分布式投票系统solidity合约代码

pragma solidity ^ 0.4.26;

contract Ballot {
    string public name; //投票的名称，name of the Ballot
    address public chairman; //合约拥有者的地址
    bool public closed; // 记录投票是否结束

    // 获胜票数比例
    uint public proportion; // 获胜时得票数占总票数的最低比例, 例如50%就赋值为50
    uint public totalVotes; // 总票数

    // 加投票权集合, 表示哪些人有投票权
    address[] voters;
    struct Proposal { // 候选人信息的结构体
        bytes32 name;
        uint voteCount;  // 候选人的得票数
    }
    Proposal[] public proposals;  // 候选人的结构体(可变长)数组
    mapping(address => bool) voteRecords; // 投票者是否投票(默认false)
    uint[] winningProposals = [0];
    bytes32[] winningProposalsName; // 记录winning候选人名字的数组

    constructor(string _name, bytes32[] _proposals, uint _proportion, address[] _voters) public { // 合约的构造函数
        chairman = msg.sender; // 记录合约的拥有者
        closed = false; // 合约默认处于打开
        name = _name; // 投票的名称，如 "选举学生会主席"
        for(uint i = 0; i < _proposals.length; i++) {
            proposals.push(Proposal({
                name: _proposals[i],
                voteCount: 0
            }));
        }
        proportion = _proportion;
        voters = _voters;
        totalVotes = voters.length;
    }


    function setChairman(address _chairman) external { // 更换合约拥有者时用
        chairman = _chairman;
    }

    function vote(uint proposal) public { //给候选人投票, 需传入候选人的序号及投票者的地址
        address voterAddress = msg.sender;
        require(!closed, "the ballot is already closed."); // 保证合约没有关闭，即投票没有结束
        // 看投票者的地址是否在合法名单中
        bool legal = false;
        for(uint i = 0; i < voters.length; i++){
            if(voters[i] == voterAddress){
                legal = true;
                break;
            }
        }
        require(legal, "the voter is illeagal!");
        require(proposal < proposals.length, "the prosal is invalid!");
        require(!voteRecords[voterAddress], "Already voted."); // 保证投票者没有投过票
        voteRecords[voterAddress] = true;

        proposals[proposal].voteCount += 1; // 候选人得票数加一
    }

    function closeBallot() public { // 关闭投票
        require(chairman == msg.sender, "only the chairman can close the ballot."); // 只有拥有者可以关闭投票
        closed = true;
    }

    function getWinningProposals() internal { //统计投票的获胜者
        winningProposals.length = 0;
        uint winningVoteCount = 0;
        for(uint i = 0; i < proposals.length; i++) {
            if(proposals[i].voteCount * 100 / totalVotes >= proportion) {
                winningProposals.push(i);
            }
        }
        if(winningProposals.length == 0){
        for(i = 0; i < proposals.length; i++){
            if(proposals[i].voteCount > winningVoteCount){
                winningVoteCount = proposals[i].voteCount;
            }
        }
        for(i = 0; i < proposals.length; i++){
            if(proposals[i].voteCount == winningVoteCount){
                winningProposals.push(i);
            }
        }
    }
    }

    function winnerName() public view returns (bytes32[]) { // 返回得票数最高的候选人的名字
        require(closed, "only when the ballot is closed can you examine the winner");
        getWinningProposals();
        for(uint i = 0; i < winningProposals.length; i++){
            winningProposalsName.push(proposals[winningProposals[i]].name);
        }
        return winningProposalsName;
    }

    function getProposalNumber() public view returns (uint){
        return proposals.length;
    }

}