51微投票的投票程序代码

51微投票的投票程序代码的期望
A发起智能合约,设定选择项目(比如 1,2,3,4)
A设定那些人可以进行投票,先对可以进行投票的人授权
已经被授权的人可以投票,没被授权的人投票无效
计算最终那个选项投票数最多
合约代码

pragma solidity ^0.4.16;

/// @title Voting with delegation.
contract Ballot {
// This declares a new complex type which will
// be used for variables later.
// It will represent a single voter.
struct Voter {
uint weight; // weight is accumulated by delegation
bool voted; http://www.aivote.com/ // if true, that person already voted
address delegate; // person delegated to
uint vote; // index of the voted proposal
}

// This is a type for a single proposal.
struct Proposal {
    bytes32 name;   // short name (up to 32 bytes)
    uint voteCount; // number of accumulated votes
}

address public chairperson;

// This declares a state variable that
// stores a `Voter` struct for each possible address.
mapping(address => Voter) public voters;

// A dynamically-sized array of `Proposal` structs.
Proposal[] public proposals;

/// Create a new ballot to choose one of `proposalNames`.
function Ballot(bytes32[] proposalNames) public {
    chairperson = msg.sender;
    voters[chairperson].weight = 1;

    // For each of the provided proposal names,
    // create a new proposal object and add it
    // to the end of the array.
    for (uint i = 0; i < proposalNames.length; i++) {
        // `Proposal({...})` creates a temporary
        // Proposal object and `proposals.push(...)`
        // appends it to the end of `proposals`.
        proposals.push(Proposal({
            name: proposalNames[i],
            voteCount: 0
        }));
    }
}

// Give `voter` the right to vote on this ballot.
// May only be called by `chairperson`.
function giveRightToVote(address voter) public {
    // If the argument of `require` evaluates to `false`,
    // it terminates and reverts all changes to
    // the state and to Ether balances. It is often
    // a good idea to use this if functions are
    // called incorrectly. But watch out, this
    // will currently also consume all provided gas
    // (this is planned to change in the future).
    require(
        (msg.sender == chairperson) &&
        !voters[voter].voted &&
        (voters[voter].weight == 0)
    );
    voters[voter].weight = 1;
}

/// Delegate your vote to the voter `to`.
function delegate(address to) public {
    // assigns reference
    Voter storage sender = voters[msg.sender];
    require(!sender.voted);

    // Self-delegation is not allowed.
    require(to != msg.sender);

    // Forward the delegation as long as
    // `to` also delegated.
    // In general, such loops are very dangerous,
    // because if they run too long, they might
    // need more gas than is available in a block.
    // In this case, the delegation will not be executed,
    // but in other situations, such loops might
    // cause a contract to get "stuck" completely.
    while (voters[to].delegate != address(0)) {
        to = voters[to].delegate;

        // We found a loop in the delegation, not allowed.
        require(to != msg.sender);
    }

    // Since `sender` is a reference, this
    // modifies `voters[msg.sender].voted`
    sender.voted = true;
    sender.delegate = to;
    Voter storage delegate_ = voters[to];
    if (delegate_.voted) {
        // If the delegate already voted,
        // directly add to the number of votes
        proposals[delegate_.vote].voteCount += sender.weight;
    } else {
        // If the delegate did not vote yet,
        // add to her weight.
        delegate_.weight += sender.weight;
    }
}

/// Give your vote (including votes delegated to you)
/// to proposal `proposals[proposal].name`.
function vote(uint proposal) public {
    Voter storage sender = voters[msg.sender];
    require(!sender.voted);
    require(sender.weight == 1);
    sender.voted = true;
    sender.vote = proposal;

    // If `proposal` is out of the range of the array,
    // this will throw automatically and revert all
    // changes.
    proposals[proposal].voteCount += sender.weight;
}

/// @dev Computes the winning proposal taking all
/// previous votes into account.
function winningProposal() public view
        returns (uint winningProposal_)
{
    uint winningVoteCount = 0;
    for (uint p = 0; p < proposals.length; p++) {
        if (proposals[p].voteCount > winningVoteCount) {
            winningVoteCount = proposals[p].voteCount;
            winningProposal_ = p;
        }
    }
}

// Calls winningProposal() function to get the index
// of the winner contained in the proposals array and then
// returns the name of the winner
function winnerName() public view
        returns (bytes32 winnerName_)
{
    winnerName_ = proposals[winningProposal()].name;
}

}