solidity投票智能合约代码

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pragma solidity >=0.7.0 <0.9.0;   //投票实验 contract Ballot{       struct Voter{         uint weight;//投票(单票)权重         bool voted;//是否投过票，true为投过票，bool类型默认值为false         address delegate;//想要委托投票的节点地址，address默认值为0x0         uint vote;//想要投票的节点的索引值(被投票节点信息用一维数组proposals存储)     }           struct Proposal{//被投票节点的相关参数         bytes32 name;//被投票节点的姓名标识         uint voteCount;//累积被投票数     }       address public chairperson;//投票管理员地址     mapping(address => Voter) public voters;//地址对投票节点的信息的映射     Proposal[] public proposals;//一维数组存储被投票节点信息       //构造方法、构造函数     //solidity和其他语言不一样，构造函数仅在部署合约时调用一次，后续调用合约不调用其构造函数     //且一个合约只能有一个构造函数，不能进行构造函数重载     constructor(bytes32[] proposalNames) public{         chairperson = msg.sender;//将第一次调用该合约的节点设置为管理员         voters[chairperson].weight = 1;//将管理员投票权置为1           for(uint i=0; i<proposalNames.length; i++){             //将所有被投票人姓名初始化进一维数组proposals，并将其对应票数初始化为0票             //.push()，括号中内容需要强调数据类型，eg:arr.push(uint(6));             proposals.push(Proposal({                 name:proposalNames[i],                 voteCount:0             }));         }     }       //由管理员授权可投票节点     function giveRightToVote(address voter) public{         //require中判断条件为false时，输出字符串"xxx..."，异常会被抛出，程序执行会被挂起，         //未消耗的gas会被退回，合约状态会回退到初始状态         require(             msg.sender == chairperson,"Only chairperson can give right to vote."         );//执行此function的节点一定为管理员节点         require(             !voters[voter].voted,"The voter already voted."         );//若voter没投过票         require(voters[voter].weight == 0);         //调用合约的人是管理员、待授权节点还没投过票、带授权节点投票权重为0时，进行授权         voters[voter].weight = 1;//上述三个require()均成立时，授权票数     }       //投票授权     function delegate(address to) public{         Voter storage sender = voters[msg.sender];         require(!sender.voted, "You already voted.");         require(to != msg.sender,"Self-delegation is disallowed.");         //sender满足的条件：要有投票权限、没有投过票、被授权节点不是自己           //判断代理节点地址是否为空：address(0)或者address(0x0)         while(voters[to].delegate != address(0)){             to = voters[to].delegate;//找到最终的代理节点             require(to != msg.sender,"Found loop in delegation.");//若代理节点最终是自己则回退到初始状态         }           sender.voted = true;//票权代理出去，状态改为已投票         sender.delegate = to;//票权代理地址         Voter storage delegate_ = voters[to];//取出代理节点状态           //若代理节点已投过票，将新代理的票权投出去，反之则将代理节点票权加和         if(delegate_.voted){             proposals[delegate_.vote].voteCount += sender.weight;         }else{             delegate_.weight += sender.weight;         }     }       function vote(uint proposal) public{         Voter storage sender = voters[msg.sender];//通过地址获取对应投票信息         require(!sender.voted,"Already voted.");//若sender未投过票         sender.voted = true;//更改投票状态为已投过票         sender.vote = proposal;//保存已投票节点         proposals[proposal].voteCount += sender.weight;//票权加和     }       //返回票数最多的节点在一维数组proposals中的索引     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;             }         }     }     //输出票数最多的节点name     function winnerName() public view returns(bytes32 winnerName_){         winnerName_ = proposals[winningProposal()].name;     } }

来源于solidity文档官网：https://docs.soliditylang.org/en/v0.8.13/solidity-by-example.html