Solidity mode pragma solidity >=0.4.22 <0.6.0; pragma solidity ^0.5.6 ; contract Ballot { struct Voter { uint weight; bool voted; uint8 vote; address delegate; } struct Proposal { uint voteCount; } address chairperson; mapping(address => Voter) voters; Proposal[] proposals; /// Create a new ballot with $(_numProposals) different proposals. constructor(uint8 _numProposals) public { chairperson = msg.sender; voters[chairperson].weight = 1; proposals.length = _numProposals; } /// Give $(toVoter) the right to vote on this ballot. /// May only be called by $(chairperson). function giveRightToVote(address toVoter) public { if (msg.sender != chairperson || voters[toVoter].voted) return; voters[toVoter].weight = 1; } /// Delegate your vote to the voter $(to). function delegate(address to) public { Voter storage sender = voters[msg.sender]; // assigns reference if (sender.voted) return; while (voters[to].delegate != address(0) && voters[to].delegate != msg.sender) to = voters[to].delegate; if (to == msg.sender) return; sender.voted = true; sender.delegate = to; Voter storage delegateTo = voters[to]; if (delegateTo.voted) proposals[delegateTo.vote].voteCount += sender.weight; else delegateTo.weight += sender.weight; } /// Give a single vote to proposal $(toProposal). function vote(uint8 toProposal) public { Voter storage sender = voters[msg.sender]; if (sender.voted || toProposal >= proposals.length) return; sender.voted = true; sender.vote = toProposal; proposals[toProposal].voteCount += sender.weight; } function winningProposal() public view returns (uint8 _winningProposal) { uint256 winningVoteCount = 0; for (uint8 prop = 0; prop < proposals.length; prop++) if (proposals[prop].voteCount> winningVoteCount) { winningVoteCount = proposals[prop].voteCount; _winningProposal = prop; } } } MIME type: text/x-solidity