Chapter 3, Problem 1PP

Calculator Write a program that allows the user to specify two numbers and then adds, subtracts, or multiplies them when the user clicks on the appropriate button. The output should give the type of arithmetic performed and the result. See Fig. 3.61. Note: When one of the numbers in an input text box is changed, the output text box should be cleared.

Program Plan Intro

Implementation of a program to create a calculator which performs addition, subtraction, and multiplication.

Program Plan:

Write a program which creates a calculator having two input text boxes in which the numbers are entered by the user.

The user can click on any of the three buttons of addition, subtraction, and multiplication.

Whichever button is clicked, it’s result will be calculated and displayed on the output textbox.

Program Description Answer

Program Description:

The program works for the creation of a calculator which adds, subtracts, or multiplies the two numbers entered by the user in two separate textboxes and displays the calculation in the output textbox.

There are two textboxes which take input from the user for the first number and the second number.

Three buttons, one for addition, second for subtraction, and the third for multiplication are created.

On clicking the respective buttons, the output textbox will display the calculation.

Explanation of Solution

Program:

Public Class Calculator

'Declare variable.

Dim var2 As Integer

'Declare variable.

Dim var1 As Integer

'Declare variable.

Dim result As Integer

'Create the event for the textbox.

Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged

'Assign value

var1 = TextBox1.Text

'Assign text to the textbox.

TextBox3.Text = var1

'Ending the function

End Sub

'Create text box event.

Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs) Handles TextBox2.TextChanged

'Assign text to the textbox.

var2 = TextBox2.Text

End Sub

'Create a button click event

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

result = var1 + var2

'Assign text to the textbox.

TextBox3.Text = var1 & "+" & var2 & "=" & result

End Sub

'Create a button click evetn

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click

result = var1 - var2

'Assign text to the textbox.

TextBox3.Text = var1 & "-" & var2 & "=" & result

End Sub

'Create a button click event

Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click

result = var1 * var2

'Assign text to the textbox.

TextBox3.Text = var1 & "*" & var2 & "=" & result

End Sub

End Class

Sample Output

On pressing the addition button:

On pressing the subtraction button:

On pressing the multiplication button: