Solidity实现投票功能-58码农网

使用solidity实现基本的投票并且去操作功能，像是投票，发票或是委託票等。

创建contract

Solidity by Example — Solidity 0.8.10 documentation (soliditylang.org)

// SPDX-License-Identifier: GPL-3.0pragma solidity >=0.7.0 <0.9.0;/// @title Voting with delegation.contract Voting {        // 选民    struct Voter {        uint weight; // weight is accumulated by delegation        bool voted;  // if true, that person already voted        address delegate; // 被委託人 person delegated to        uint vote;   // 投票提案的索引 index of the voted proposal    }    // This is a type for a single proposal.    struct Proposal {        string 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;    // 为`proposalNames` 中的每个提案，创建一个新投票表决 Create a new ballot to choose one of `proposalNames`.    constructor(string[] memory proposalNames) {        chairperson = msg.sender;        voters[chairperson].weight = 1;        // 对每一提案名称，创建一个新的Proposal并添加到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            }));        }    }    // 授权voter对这个表决进行投票，只有chairperson能调用此函数    function giveRightToVote(address voter) external {        // If the first argument of `require` evaluates        // to `false`, execution terminates and all        // changes to the state and to Ether balances        // are reverted.        // This used to consume all gas in old EVM versions, but        // not anymore.        // It is often a good idea to use `require` to check if        // functions are called correctly.        // As a second argument, you can also provide an        // explanation about what went wrong.        require(            msg.sender == chairperson,            "Only chairperson can give right to vote."        );        require(            !voters[voter].voted,            "The voter already voted."        );        require(voters[voter].weight == 0);        voters[voter].weight = 1;    }    /// 将您的投票委託给选民 voter `to`.    function delegate(address to) external {        // assigns reference        Voter storage sender = voters[msg.sender];        require(!sender.voted, "You already voted.");        require(to != msg.sender, "Self-delegation is disallowed.");        // 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, "Found loop in delegation.");        }        // 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;        }    }    /// 把你的票(包括委託给你的票)，投给提案`proposals[proposal].name`.    function vote(uint proposal) external {        Voter storage sender = voters[msg.sender];        require(sender.weight != 0, "Has no right to vote");        require(!sender.voted, "Already 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() 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() external view            returns (string memory winnerName_)    {        winnerName_ = proposals[winningProposal()].name;    }}