How to vote more times in an elections smart contract?

Question

I have a simple copied smart contract for elections, where a voter votes only one time for one candidate, and then is denied to vote more times.

But would it be possible to allow the voter to vote up to 3 times and sending a vote to a different candidate each time? Meaning when you send more than one vote to one candidate, you would be denied. How would it be done?

The code

contract Election {

struct Candidate {
    string name;
    uint voteCount;
}
struct Voter {
    uint voteIndex;
    bool voted;
    uint weight;
}

address public owner;
string public name;
mapping(address => Voter) public voters;
Candidate[] public candidates;
uint public auctionEnd;

event ElectionResult(string name, uint voteCount);

function Election(string _name, uint durationMinutes, string candidate1, string candidate2, string candidate3, string candidate4, string candidate5) public{
    owner = msg.sender;
    name = _name; 
    auctionEnd = now + (durationMinutes * 1 minutes);

    candidates.push(Candidate(candidate1, 0));
    candidates.push(Candidate(candidate2, 0));
    candidates.push(Candidate(candidate3, 0));
    candidates.push(Candidate(candidate4, 0));
    candidates.push(Candidate(candidate5, 0));
}

function authorize(address voter) public {
    require(msg.sender == owner);
    require(!voters[voter].voted);

    voters[voter].weight = 1;

}

function vote(uint voteIndex) public {
    require(now < auctionEnd);
    require(!voters[msg.sender].voted);

    voters[msg.sender].voted = true;
    voters[msg.sender].voteIndex = voteIndex;

    candidates[voteIndex].voteCount += voters[msg.sender].weight;
}

function end() public {
    require(msg.sender == owner);
    require(now >= auctionEnd);

    for(uint i=0; i < candidates.length; i++) {
        ElectionResult(candidates[i].name, candidates[i].voteCount);
    }
}
}

Answer 1

I agree with @Nulik that this is more generally about programming. You want to change the rules. Basically, instead of checking if the voter ever volted, you want to change how many times they voted.

This

struct Voter {
    uint voteIndex;
    bool voted;  // <= ever voted
    uint weight;
}

To this:

struct Voter {
    uint voteIndex;
    uint voted; // <== count of votes cast
    uint weight;
}

This

require(!voters[voter].voted);

To this

require(voters[voter].voted < 3);

This

voters[msg.sender].voted = true;

To this

voters[msg.sender].voted += 1;

This is by no means thoroughly tested and there is no warranty. It may be a start for educational purposes only.

Hope it helps.