Created using remix-ide: Realtime Ethereum Contract Compiler and Runtime. Load this file by pasting this gists URL or ID at https://remix.ethereum.org/#version=soljson-v0.4.23+commit.124ca40d.js&optimize=false&gist=

ballot.sol

pragma solidity ^0.4.0;
contract Ballot {

    struct Voter {
        uint weight;
        bool voted;
        uint8 vote;
        address delegate;
    }
    struct Proposal {
        uint voteCount;
    }

    address chairperson;
    mapping(address => Voter) voters;
    Proposal[] proposals;

    /// Create a new ballot with $(_numProposals) different proposals.
    function Ballot(uint8 _numProposals) public {
        chairperson = msg.sender;
        voters[chairperson].weight = 1;
        proposals.length = _numProposals;
    }

    /// Give $(toVoter) the right to vote on this ballot.
    /// May only be called by $(chairperson).
    function giveRightToVote(address toVoter) public {
        if (msg.sender != chairperson || voters[toVoter].voted) return;
        voters[toVoter].weight = 1;
    }

    /// Delegate your vote to the voter $(to).
    function delegate(address to) public {
        Voter storage sender = voters[msg.sender]; // assigns reference
        if (sender.voted) return;
        while (voters[to].delegate != address(0) && voters[to].delegate != msg.sender)
            to = voters[to].delegate;
        if (to == msg.sender) return;
        sender.voted = true;
        sender.delegate = to;
        Voter storage delegateTo = voters[to];
        if (delegateTo.voted)
            proposals[delegateTo.vote].voteCount += sender.weight;
        else
            delegateTo.weight += sender.weight;
    }

    /// Give a single vote to proposal $(toProposal).
    function vote(uint8 toProposal) public {
        Voter storage sender = voters[msg.sender];
        if (sender.voted || toProposal >= proposals.length) return;
        sender.voted = true;
        sender.vote = toProposal;
        proposals[toProposal].voteCount += sender.weight;
    }

    function winningProposal() public constant returns (uint8 _winningProposal) {
        uint256 winningVoteCount = 0;
        for (uint8 prop = 0; prop < proposals.length; prop++)
            if (proposals[prop].voteCount > winningVoteCount) {
                winningVoteCount = proposals[prop].voteCount;
                _winningProposal = prop;
            }
    }
}

RealEstateMarket.sol

pragma solidity ^0.4.18;
pragma experimental ABIEncoderV2;

contract RealEstateMarket {
    struct RealEstate {
        string image;
        string description;
        uint price;
        address owner;
    }
    RealEstate[] realEstates;
    
    function addRealEstate(address _owner, string image, string description, uint price) {
        realEstates.length++;
        
        realEstates[realEstates.length - 1].image = image;
        realEstates[realEstates.length - 1].description = description;
        realEstates[realEstates.length - 1].price = price;
        realEstates[realEstates.length - 1].owner = _owner;
    }
    
    function getRealEstatesLength() view public returns (uint) {
        return realEstates.length;
    }
    
    function getRealEstate(uint id) public returns (string, string, uint, address) {
        return (realEstates[id].image, realEstates[id].description, realEstates[id].price, realEstates[id].owner);
    }
    
    function buyRealEstate(uint id, address newOwner) {
        realEstates[id].owner = newOwner;
    } 
}