BYNNRw4F

1pragma solidity ^0.4.18;
2
3////////////////////////  Voting.sol - 1  ////////////////////////////////////////////
4
5// written for Solidity version 0.4.18 and above that doesn't break functionality 
6contract Voting {
7
8    // an event that is called whenever a Candidate is added so the frontend could
9    // appropriately display the candidate with the right element id (it is used
10    // to vote for the candidate, since it is one of arguments for the function
11    //"vote")
12    event AddedCandidate(uint candidateID);
13    
14    // describes a Voter, which has an id and the ID of the candidate they voted for
15    address owner;
16    
17    function Voting() public {
18        owner=msg.sender; 
19    }
20    
21////////////////////////  Voting.sol - 2  ////////////////////////////////////////////
22    
23    modifier onlyOwner {
24        // describes a Candidate
25        require(msg.sender == owner);
26        _;
27    }
28    
29    struct Voter {
30        uint candidateIDVote; // this flag will help authorization of voter
31        bool isAuthorized;
32        bool hasVoted;  // this flag will help to keep track of 1 voter - 1 vote
33    }
34
35    // describes a Candidate
36    struct Candidate {
37        string name;
38        string party;
39        uint noOFVotes;
40        bool doesExist; // "bool doesExist" is to check if this Struct exists
41    }
42    
43    // This is so we can keep track of the candidates
44    
45////////////////////////  Voting.sol - 3  ////////////////////////////////////////////
46    
47    // These state variables are used keep track of the number of Candidates/Voters
48    // and used to as a way to index them
49    uint numCandidates; // declares a state variable - number Of Candidates
50    uint numVoters;
51    uint numOfVotes;
52    
53    // Think of these as a hash table, with the key as a uint and value of
54    // the struct Candidate/Voter. These mappings will be used in the majority
55    // of our transactions/calls
56    // These mappings will hold all the candidates and Voters respectively
57    mapping (uint => Candidate) candidates;
58    mapping (address => Voter) voters;
59    
60    
61////////////////////////  Voting.sol - 4  ////////////////////////////////////////////
62    
63    /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
64    *
65    These functions perform transactions, editing the mappings *
66    * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
67    
68    function addCandidate(string name, string party) onlyOwner public {
69        // candidateID is the return variable
70        uint candidateID = numCandidates++;
71        // Create new Candidate Struct with name and saves it to storage.
72        candidates[candidateID] = Candidate(name,party,0,true);
73        AddedCandidate(candidateID);
74    }
75    
76////////////////////////  Voting.sol - 5  ////////////////////////////////////////////
77
78    function vote(uint candidateID) public {
79        // checks if the struct exists for that candidate
80        require(!voters[msg.sender].hasVoted);// this statement is to check this voter is not already voted
81        require(voters[msg.sender].isAuthorized);
82        if (candidates[candidateID].doesExist == true) {
83            voters[msg.sender] = Voter(candidateID, true, true);
84            candidates[candidateID].noOFVotes++;
85            numOfVotes++;
86            numVoters++;
87        }
88    }
89    
90////////////////////////  Voting.sol - 6  ////////////////////////////////////////////
91
92    /* * * * * * * * * * * * * * * * * * * * * * * * * *
93    *
94    Getter Functions, marked by the key word "view" *
95    * * * * * * * * * * * * * * * * * * * * * * * * * */
96    // finds the total amount of votes for a specific candidate by looping
97    //through voters
98    function totalVotes(uint candidateID) view public returns (uint) {
99        return candidates[candidateID].noOFVotes;
100    }
101    
102////////////////////////  Voting.sol - 7  ////////////////////////////////////////////
103    
104    function getNumOfCandidates() public view returns(uint) {
105        return numCandidates;
106    }
107    
108    function getNumOfVoters() public view returns(uint) {
109        return numVoters;
110    }
111    
112    // returns candidate information, including its ID, name, and party
113    function getCandidate(uint candidateID) public view returns(uint,string,string,uint)
114    {
115        return (candidateID,candidates[candidateID].name,candidates[candidateID].party,candidates[candidateID].noOFVotes);
116    } 
117    
118////////////////////////  Voting - Assignment  ////////////////////////////////////////////
119
120    function Authorize(address _Voter) onlyOwner public {
121        voters[_Voter].isAuthorized = true;
122    }
123    
124}