I am trying below code to write Voting Contract referring to Solidity documentation pdf.

Code compiles without error but I am getting below error while deploying.

writing Ballot to app\meta\Ballot\Ballot.json
wrote: app\meta\Ballot\Ballot.json
caught a single contract
uploading Ballot
upload contract: Ballot
there was an error: {"errorTags":["Solidity","Solidity"],"message":"function \"Ballot\" arguments must include \"proposalNames\""}
POST /users/testuser/HashKeyRemoved/contract 200 525.540 ms - 24

Code -

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; // 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) {
        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`.
                name: proposalNames[i],
                voteCount: 0

    // Give `voter` the right to vote on this ballot.
    // May only be called by `chairperson`.
    function giveRightToVote(address voter) {
        if (msg.sender != chairperson || voters[voter].voted) {
            // `throw` 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 also consume all provided gas.
        voters[voter].weight = 1;

    /// Delegate your vote to the voter `to`.
    function delegate(address to) {
        // assigns reference
        Voter sender = voters[msg.sender];
        if (sender.voted)
        // 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) &&
            voters[to].delegate != msg.sender
            ) {
            to = voters[to].delegate;
        // We found a loop in the delegation, not allowed.
        if (to == msg.sender) {
        // Since `sender` is a reference, this
        // modifies `voters[msg.sender].voted`
        sender.voted = true;
        sender.delegate = to;

        Voter 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) {
        Voter sender = voters[msg.sender];
        if (sender.voted)
        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() constant
        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;
  • Thus is most likely an issue with your deployment method, not the contract itself. What is the process you're using to deploy the contract? From the error, I would guess you need to supply an argument to the constructor Sep 12, 2016 at 2:20
  • I am using Visual Studio to deploy. You are right I am missing to pass argument to constructor. But I am newbee to this, so dont know how do I exactly pass argument value to constructor. I am going to try below, hope that works. bytes32[] proposalNames={"FirstProposal","SecondProposal"}; Ballot b = new Ballot(proposalNames);
    – RaisKazi
    Sep 12, 2016 at 2:31
  • If you will compile the code from solidity browser, you will get the space left (as comments) in the compiled code where you just need to put the value: like this - var proposalNames = /* var of type bytes32[] here */ ;
    – Aniket
    Sep 12, 2016 at 5:39
  • You use a number of anti-patterns. Do not use un-bounded for() or while() loops because you will run out of gas. For instance, you should tally votes as they come in. Sep 12, 2016 at 11:12
  • Can you show the line that deploys your contract? Sep 12, 2016 at 19:13

3 Answers 3


In order to deploy the contract you need to pass array of bytes32 into constructor, it should look like ["0x..", "0x.."]

In order to convert strings to bytes32 you can use for instance web3.fromAscii('FirstProposal', 32)


You should use some other tools to deploy, like truffle, it is very convenient to use. The reason is:
1: you have params to create your contract
2: when you deploy your contract to other test network or main network, you can not use VS to deploy. And maybe you need to migrate your contract in the later.


You should add the proposals array when you deploy your contract, the proposal has to be an array of bytes32 something like ["0x...","0x...","0x..."]

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