votingSys.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract Voting {
    //━━━━━━━━━━━━━initialization━━━━━━━━━━━━━━━━━━//

    struct Candidate {
        uint256 id;
        string name;
        string party;
        string gender;
        uint256 age;
        address Address;
        uint256 votes;
    }
    struct Voter {
        uint256 id;
        string name;
        string gender;
        uint256 age;
        uint256 voteCandidateId;
        address Address;
    }

    mapping(uint256 => Candidate) public candidateDetails;
    mapping(uint256 => Voter) public VoterDetails;

    uint256 candidateId = 1;
    uint256 VoterId = 1;

    //━━━━━━━━━━━━━functions━━━━━━━━━━━━━━━━━━//

    function CandidateRegister(
        string calldata _name,
        string calldata _party,
        string calldata _gender,
        uint256 _age
    ) public {
        require(
            CandidateVerification(msg.sender),
            "Candidate account is already exist !!"
        );

        candidateDetails[candidateId] = Candidate(
            candidateId,
            _name,
            _party,
            _gender,
            _age,
            msg.sender,
            0
        );
        candidateId += 1;
    }

    function CandidateVerification(address _sender)
        private
        view
        returns (bool)
    {
        for (uint256 i = 0; i < candidateId; i++) {
            if (candidateDetails[i].Address == _sender) {
                return false;
            }
        }
        return true;
    }

    function CandidateList() public view returns (Candidate[] memory) {
        Candidate[] memory array = new Candidate[](candidateId - 1);
        for (uint256 i = 1; i < candidateId; i++) {
            array[i - 1] = candidateDetails[i];
        }
        return array;
    }

    function VoterRegister(
        string calldata _name,
        string calldata _gender,
        uint256 _age
    ) public {
        require(
            VoterVerification(msg.sender),
            "Voter account is already register"
        );
        require(_age >= 18, "Voter person age is smaller");
        VoterDetails[VoterId] = Voter(
            VoterId,
            _name,
            _gender,
            _age,
            0,
            msg.sender
        );
        VoterId += 1;
    }

    function VoterVerification(address _sender) private view returns (bool) {
        for (uint256 i = 1; i < VoterId; i++) {
            if (VoterDetails[i].Address == _sender) {
                return false;
            }
        }
        return true;
    }

    function VoterList() public view returns (Voter[] memory) {
        Voter[] memory array = new Voter[](VoterId - 1);
        for (uint256 i = 1; i < VoterId; i++) {
            array[i - 1] = VoterDetails[i];
        }
        return array;
    }

    function vote(uint256 _voterId, uint256 _candidateId) public {
        require(VoterDetails[_voterId].voteCandidateId == 0, "already voted");
        require(
            VoterDetails[_voterId].Address == msg.sender,
            "you are not a valid voter"
        );
        require(
            candidateDetails[_candidateId].id == _candidateId,
            "Candidate is not register"
        );

        VoterDetails[_voterId].voteCandidateId = _candidateId;
        candidateDetails[_candidateId].votes += 1;
    }

    function WinnerCheck() public view returns (string memory) {
        string memory winnerName = "tie";
        uint256 maxVotes = 0;

        for (uint256 i = 1; i <= candidateId; i++) {
            if (candidateDetails[i].votes > maxVotes) {
                maxVotes = candidateDetails[i].votes;
                winnerName = candidateDetails[i].name;
            }
        }
        return winnerName;
    }
}