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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`.
            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) {
        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.
            throw;
        }
        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)
            throw;
        // 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) {
            throw;
        }
        // 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)
            throw;
        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 – Tjaden Hess Sep 12 '16 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 '16 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 '16 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. – Xavier Leprêtre B9lab Sep 12 '16 at 11:12
  • Can you show the line that deploys your contract? – Xavier Leprêtre B9lab Sep 12 '16 at 19:13
0

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.

0

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)

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