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Etapa 7: Adicionar problemas de multiplicação e divisão

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Na sétima parte deste tutorial, você adicionará problemas de multiplicação e de divisão, mas primeiro pense em como fazer essa alteração.Considere a etapa inicial, que envolve armazenar valores.

Para adicionar problemas de multiplicação e de divisão

  1. Adicione mais quatro variáveis inteiras ao formulário.

    Public Class Form1

    ' Create a Random object called randomizer  
    ' to generate random numbers. 
    Private randomizer As New Random

    ' These integer variables store the numbers  
    ' for the addition problem.  
    Private addend1 As Integer 
    Private addend2 As Integer 


    ' These integer variables store the numbers  
    ' for the subtraction problem.  
    Private minuend As Integer 
    Private subtrahend As Integer 

    ' These integer variables store the numbers  
    ' for the multiplication problem.  
    Private multiplicand As Integer 
    Private multiplier As Integer 

    ' These integer variables store the numbers  
    ' for the division problem.  
    Private dividend As Integer 
    Private divisor As Integer 

    ' This integer variable keeps track of the  
    ' remaining time. 
    Private timeLeft As Integer

    public partial class Form1 : Form
{
    // Create a Random object called randomizer  
    // to generate random numbers.
    Random randomizer = new Random();

    // These integer variables store the numbers  
    // for the addition problem.  
    int addend1;
    int addend2;

    // These integer variables store the numbers  
    // for the subtraction problem.  
    int minuend;
    int subtrahend;

    // These integer variables store the numbers  
    // for the multiplication problem.  
    int multiplicand;
    int multiplier;

    // These integer variables store the numbers  
    // for the division problem.  
    int dividend;
    int divisor;

    // This integer variable keeps track of the  
    // remaining time. 
    int timeLeft;

  2. Como você fez antes, modifique o método de StartTheQuiz() para preencher números aleatórios para os problemas de multiplicação e de divisão.

    ''' <summary> 
''' Start the quiz by filling in all of the problem  
''' values and starting the timer.  
''' </summary> 
''' <remarks></remarks> 
Public Sub StartTheQuiz()

    ' Fill in the addition problem. 
    ' Generate two random numbers to add. 
    ' Store the values in the variables 'addend1' and 'addend2'.
    addend1 = randomizer.Next(51)
    addend2 = randomizer.Next(51)

    ' Convert the two randomly generated numbers 
    ' into strings so that they can be displayed 
    ' in the label controls.
    plusLeftLabel.Text = addend1.ToString()
    plusRightLabel.Text = addend2.ToString()

    ' 'sum' is the name of the NumericUpDown control. 
    ' This step makes sure its value is zero before 
    ' adding any values to it.
    sum.Value = 0

    ' Fill in the subtraction problem.
    minuend = randomizer.Next(1, 101)
    subtrahend = randomizer.Next(1, minuend)
    minusLeftLabel.Text = minuend.ToString()
    minusRightLabel.Text = subtrahend.ToString()
    difference.Value = 0

    ' Fill in the multiplication problem.
    multiplicand = randomizer.Next(2, 11)
    multiplier = randomizer.Next(2, 11)
    timesLeftLabel.Text = multiplicand.ToString()
    timesRightLabel.Text = multiplier.ToString()
    product.Value = 0

    ' Fill in the division problem.
    divisor = randomizer.Next(2, 11)
    Dim temporaryQuotient As Integer = randomizer.Next(2, 11)
    dividend = divisor * temporaryQuotient
    dividedLeftLabel.Text = dividend.ToString()
    dividedRightLabel.Text = divisor.ToString()
    quotient.Value = 0

    ' Start the timer.
    timeLeft = 30
    timeLabel.Text = "30 seconds"
    Timer1.Start()

End Sub

    /// <summary> 
/// Start the quiz by filling in all of the problem  
/// values and starting the timer.  
/// </summary> 
public void StartTheQuiz()
{
    // Fill in the addition problem. 
    // Generate two random numbers to add. 
    // Store the values in the variables 'addend1' and 'addend2'.
    addend1 = randomizer.Next(51);
    addend2 = randomizer.Next(51);

    // Convert the two randomly generated numbers 
    // into strings so that they can be displayed 
    // in the label controls.
    plusLeftLabel.Text = addend1.ToString();
    plusRightLabel.Text = addend2.ToString();

    // 'sum' is the name of the NumericUpDown control. 
    // This step makes sure its value is zero before 
    // adding any values to it.
    sum.Value = 0;

    // Fill in the subtraction problem.
    minuend = randomizer.Next(1, 101);
    subtrahend = randomizer.Next(1, minuend);
    minusLeftLabel.Text = minuend.ToString();
    minusRightLabel.Text = subtrahend.ToString();
    difference.Value = 0;

    // Fill in the multiplication problem.
    multiplicand = randomizer.Next(2, 11);
    multiplier = randomizer.Next(2, 11);
    timesLeftLabel.Text = multiplicand.ToString();
    timesRightLabel.Text = multiplier.ToString();
    product.Value = 0;

    // Fill in the division problem.
    divisor = randomizer.Next(2, 11);
    int temporaryQuotient = randomizer.Next(2, 11);
    dividend = divisor * temporaryQuotient;
    dividedLeftLabel.Text = dividend.ToString();
    dividedRightLabel.Text = divisor.ToString();
    quotient.Value = 0;

    // Start the timer.
    timeLeft = 30;
    timeLabel.Text = "30 seconds"; 
    timer1.Start();
}

  3. Modifique o método de CheckTheAnswer() de modo que ele também verifique os problemas de multiplicação e de divisão.

    ''' <summary> 
''' Check the answers to see if the user got everything right. 
''' </summary> 
''' <returns>True if the answer's correct, false otherwise.</returns> 
''' <remarks></remarks> 
Public Function CheckTheAnswer() As Boolean 

    If addend1 + addend2 = sum.Value AndAlso 
       minuend - subtrahend = difference.Value AndAlso 
       multiplicand * multiplier = product.Value AndAlso 
       dividend / divisor = quotient.Value Then 

        Return True 
    Else 
        Return False 
    End If 

End Function

    /// <summary> 
/// Check the answers to see if the user got everything right. 
/// </summary> 
/// <returns>True if the answer's correct, false otherwise.</returns> 
private bool CheckTheAnswer()
{
    if ((addend1 + addend2 == sum.Value)
        && (minuend - subtrahend == difference.Value)
        && (multiplicand * multiplier == product.Value)
        && (dividend / divisor == quotient.Value))
        return true;
    else 
        return false;
}

    Não é possível inserir facilmente o sinal de multiplicação (×) e o sinal de divisão (÷) usando o teclado, então o Visual C# e o Visual Basic aceitam um asterisco (*) para multiplicação e uma barra (/) para divisão.

  4. Altere a parte a mais recente do manipulador de eventos de escala do timer de modo que preencha a resposta correta quando o tempo de execução se esgotar.

    Else 
    ' If the user ran out of time, stop the timer, show 
    ' a MessageBox, and fill in the answers.
    Timer1.Stop()
    timeLabel.Text = "Time's up!"
    MessageBox.Show("You didn't finish in time.", "Sorry!")
    sum.Value = addend1 + addend2
    difference.Value = minuend - subtrahend
    product.Value = multiplicand * multiplier
    quotient.Value = dividend / divisor
    startButton.Enabled = True 
End If

    else
{
    // If the user ran out of time, stop the timer, show  
    // a MessageBox, and fill in the answers.
    timer1.Stop();
    timeLabel.Text = "Time's up!";
    MessageBox.Show("You didn't finish in time.", "Sorry");
    sum.Value = addend1 + addend2;
    difference.Value = minuend - subtrahend;
    product.Value = multiplicand * multiplier;
    quotient.Value = dividend / divisor;
    startButton.Enabled = true;
}

  5. Salve e execute seu programa.

    Os participantes de teste devem responder quatro problemas para concluir o teste, conforme mostrado na ilustração.

    Teste de matemática com quatro problemas

    Teste de matemática com quatro problemas

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