Code

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "@openzeppelin/contracts/access/Ownable.sol";

contract Voting is Ownable {
    struct Candidate {
        string name;
        uint256 voteCount;
    }

    mapping(uint256 => Candidate) public candidates;
    mapping(address => bool) public hasVoted;
    uint256 public candidatesCount;

    event Voted(address indexed voter, uint256 candidateId);

    constructor(string[] memory candidateNames) {
        for (uint256 i = 0; i < candidateNames.length; i++) {
            candidates[i] = Candidate(candidateNames[i], 0);
            candidatesCount++;
        }
    }

    function vote(uint256 candidateId) external {
        require(candidateId < candidatesCount, "Invalid candidate");
        require(!hasVoted[msg.sender], "Already voted");

        hasVoted[msg.sender] = true;
        candidates[candidateId].voteCount++;

        emit Voted(msg.sender, candidateId);
    }

    function getCandidate(uint256 candidateId) external view returns (string memory name, uint256 votes) {
        Candidate memory c = candidates[candidateId];
        return (c.name, c.voteCount);
    }
}