pragma solidity >=0.4.9 <0.6.0; /// @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; // 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`. constructor(bytes32[] memory 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 (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. revert(); } voters[voter].weight = 1; } /// Delegate your vote to the voter `to`. function delegate(address to) public { // assigns reference Voter memory sender = voters[msg.sender]; if (sender.voted) revert(); // 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) { revert(); } // Since `sender` is a reference, this // modifies `voters[msg.sender].voted` sender.voted = true; sender.delegate = to; Voter memory 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 memory sender = voters[msg.sender]; if (sender.voted) revert(); 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() view public returns (bytes32 winnerName) { winnerName = proposals[winningProposal()].name; } function testWithArray (bytes32[] memory param) public {} }