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Example Application:
Elementary Addition

 

Elementary Addition

Introduction

This exercise applies the characteristics of a label to assist you with performing elementary additions.

In this application, two numbers are selected randomly. Each number is less than 100. After the form displays these two numbers, the user (the student) is asked to add them and enter the result. The user/student can then click Check to check the result.

Windows Controls:

Practical LearningPractical Learning: Introducing Text Boxes

  1. Create a Window Forms Application named ElementaryAddition2
  2. Design the form as follows:
     
    Elementary Addition
    Control Text Name TextAlign Font Additional Properties
    Label 00 lblOperand1 Center Name: Tahoma
    Size:   48
    Bold:   True
    AutoSize: True
    ForeColor: Blue
    Label +   Center Name: Arial
    Size:   50
    Bold:   True
    AutoSize: True
    ForeColor: Maroon
    Label 00 lblOperand2 Center Name: Tahoma
    Size:   48
    Bold:   True
    AutoSize: True
    ForeColor: Blue
    Label =   Center Name: Arial
    Size:   50
    Bold:   True
    AutoSize: True
    ForeColor: Green
    TextBox 000 txtResult Center Name: Tahoma
    Size:   48
    Bold:   True
     
    Label New Operation lblNewOperation Center Name: Tahoma, Size: 28 Bold: True AutoSize: True
    BorderStyle: Fixed3D
    ForeColor: White
    BackColor:Maroon 
    Label Check lblCheckAnswer Center Name: Tahoma, Size: 28 Bold: True AutoSize: True
    BorderStyle: Fixed3D
    ForeColor: White
    BackColor:Maroon 
    Label Quit lblQuit Center Name: Tahoma, Size: 28 Bold: True AutoSize: True
    BorderStyle: FixedSingle
  3. Double-click the New Operation label and implement its event as follows:
    private void lblNewOperation_Click(object sender, EventArgs e)
    {
            int operand1;
            int operand2;
    
            Random rnd = new Random();
    
            operand1 = rnd.Next(99);
            operand2 = rnd.Next(99);
            int result = operand1 + operand2;
    
            lblOperand1.Text = operand1.ToString();
            lblOperand2.Text = operand2.ToString();
            txtResult.Text   = "";
            txtResult.Focus();
    }
  4. Return to the form and double-click the Check label
  5. Implement its event as follows:
    private void lblCheckAnswer_Click(object sender, EventArgs e)
    {
            int Operand1 = 0;
            int Operand2 = 0;
            int Result = 0;
    
            try
            {
                    Operand1 = int.Parse(lblOperand1.Text);
            }
            catch (FormatException)
            {
                    MessageBox.Show("Invalid Value");
            }
    
            try
            {
                    Operand2 = int.Parse(lblOperand2.Text);
            }
            catch (FormatException)
            {
                    MessageBox.Show("Invalid Value");
            }
    
            try
            {
                    Result = int.Parse(txtResult.Text);
            }
            catch (FormatException)
            {
                    MessageBox.Show("Invalid Answer");
            }
    
            if (Result == (Operand1 + Operand2))
                    MessageBox.Show("WOW - Good Answer");
            else
                    MessageBox.Show("PSSST - Wrong Answer");
    
            lblNewOperation_Click(sender, e);
    }
  6. Return to the form and double-click Quit
  7. Implement its event as follows:
    private void lblQuit_Click(object sender, EventArgs e)
    {
                Close();
    }
  8. Execute the application and test it
  9. Click the Close button to close the form and return to your programming environment
 

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