pragma solidity 0.5.16;

contract Election {

// Model a Candidate

struct Candidate {

uint id;

string name;

uint voteCount;

}

// Store accounts that have voted

mapping(address => bool) public voters;

// Store Candidates

mapping(uint => Candidate) public candidates;

/*Solidity tip: mapping is like an array or hashmap

// Store Candidates Count

uint public candidatesCount;

// voted event

event votedEvent (

uint indexed _candidateId

);

constructor () public {

addCandidate("Superman");

addCandidate("Batman");

}

function addCandidate (string memory _name) private {

candidatesCount ++;

candidates[candidatesCount] = Candidate(candidatesCount, _name, 0);

}

function getCandidate(uint256 _candidateId) public view returns(string memory) {

require(_candidateId > 0 && _candidateId <= candidatesCount, "Invalid Candidate ID");

return candidates[_candidateId].name;

}

function getVoteCount(uint256 _candidateId) external view returns (uint256 voteCount)

{

require(_candidateId > 0 && _candidateId <= candidatesCount, "Invalid Candidate ID");

return candidates[_candidateId].voteCount;

}

function vote (uint _candidateId) public {

// require that they haven't voted before

require(!voters[msg.sender]);

// require a valid candidate

require(_candidateId > 0 && _candidateId <= candidatesCount);

// record that voter has voted

voters[msg.sender] = true;

// update candidate vote Count

candidates[_candidateId].voteCount ++;

// trigger voted event

emit votedEvent(_candidateId);

}

}