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ballot.sol

pragma solidity >=0.4.22 <0.6.0;
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.
    constructor(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 view 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;
            }
    }
}

ballot_test.sol

import "remix_tests.sol"; // this import is automatically injected by Remix.
import "./ballot.sol";

contract test3 {
   
    Ballot ballotToTest;
    function beforeAll () public {
       ballotToTest = new Ballot(2);
    }
    
    function checkWinningProposal () public {
        ballotToTest.vote(1);
        Assert.equal(ballotToTest.winningProposal(), uint(1), "1 should be the winning proposal");
    }
    
    function checkWinninProposalWithReturnValue () public view returns (bool) {
        return ballotToTest.winningProposal() == 1;
    }
}

GuardaLoteria.sol

pragma solidity >=0.4.22 <0.6.0;

contract GuardaLoteria {
    uint numeroSorteado;

    function set(uint enviado) public {
        numeroSorteado = enviado;
    }
    
    function get() public view returns (uint) {
        return numeroSorteado;
    
        
    }
}

GuardaLoteria1.sol

pragma solidity >=0.4.22 <0.6.0;

contract GuardaLoteria1 {
    uint numeroSorteado;
    address dono;
    uint contadorDeSorteios = 0;
    bool donoRico = false;
    
    constructor(uint numeroInicial) public{
        require (msg.sender.balance > 99.99999999999 ether);
        
        numeroSorteado = numeroInicial;
        dono = msg.sender;
        contadorDeSorteios = 1;
        
        if (msg.sender.balance > 20 ether){
            donoRico = true;
        }
        else {
            donoRico = false;
        }
    }

    function set(uint enviado) public {
        numeroSorteado = enviado;
        contadorDeSorteios++;   
    }
    
    function get() public view returns (uint) {
        return numeroSorteado;
    
    }
    
    function getContador() public view returns (uint){
        return contadorDeSorteios;
        
    }
    
    function getDono()  public view returns (address){
        return dono;
    }
    
    function getRico() public view returns (bool){
        return donoRico;
    }
    
}

overflow.sol

pragma solidity >=0.4.22 <0.6.0;


contract Overflow  {
    uint16 numeroSorteado;       
    uint numeroSorteadoGrande;
    uint16 contadorDeSorteios;
    address dono;

    constructor (uint16 numeroInicial) public {
        numeroSorteado = numeroInicial;
        contadorDeSorteios = 65530;
        dono = msg.sender;
    }
    
    function set(uint enviado) public payable {
        numeroSorteadoGrande = enviado;
        numeroSorteado = uint16(enviado);
        
        require (msg.sender == dono , "Apenas o dono do contrato pode setar");
        
        require ( contadorDeSorteios +1 > contadorDeSorteios , "Overflow no contador");
        require ( numeroSorteado == numeroSorteadoGrande , "Overflow no numero");
        contadorDeSorteios++;
        
    }
    
    
      function get() public view returns (uint _numero, uint _numeroSorteadoGrande, uint16 _contador, address _dono, address _contrato, uint _saldo) {
      return (numeroSorteado,
              numeroSorteadoGrande,
              contadorDeSorteios,
              dono,
              this,
              address(this).balance);
  }
}

overflow3.sol

pragma solidity ^0.4.0;

contract Overflow {
  uint16 numeroSorteado;       // 0 a 65535 
  uint numeroSorteadoGrande;   // 0 a  2^256 -1 ou (1.1579208923731619542357098500869e+77 – 1)

  uint16 contadorDeSorteios;

  address dono;

constructor(uint16 numeroInicial) public {
  	numeroSorteado = numeroInicial;
  	contadorDeSorteios = 65530;
  	dono = msg.sender;
  }  

  function set(uint enviado) public payable {
    numeroSorteadoGrande = enviado;
    numeroSorteado = uint16(enviado);

    require (msg.sender == dono, "apenas o dono do contrato pode setar");

    require (contadorDeSorteios + 1 > contadorDeSorteios, "overflow no contador");
    require (numeroSorteado == numeroSorteadoGrande, "overflow no numero");

    contadorDeSorteios++;
  }

  function get() public view returns (uint _numero, uint _numeroSorteadoGrande, uint16 _contador, address _dono, address _contrato, uint _saldo) {
      return (numeroSorteado,
              numeroSorteadoGrande,
              contadorDeSorteios,
              dono,
              this,
              address(this).balance);
  }
}

variaveis.sol

pragma solidity >= 0.4.0;

contract GuardaLoteria {
    int8 numero;
    bool numeroPar;
    bool numeroImpar;
    
    constructor(int256  _numero) public payable {
        set (_numero);
    }
    
    function set(int256 _numero) public {
        require (_numero == int8(_numero), "Valor não cabe na variável global");
        numero = int8(_numero);
        
        numeroPar = numero % 2 == 0;
        numeroImpar = !numeroPar;
        
    }
    
    function get() public view returns (int8 _numero, bool _ePar, bool _eImpar) {
        return (numero, numeroPar, numeroImpar);
    }
}