Given a circle with radius, r:

• the formula for the area of the circle is: pi * r ^ 2 (Note: r ^ 2 means r squared)
• the formula for the circumference of the circle is: 2 * pi * r

Create a program that asks the user to enter the radius of a circle. The program should then display the area and circumference of the circle. You may use the value of 3.14 as an approximate value of pi.

Create a program that allows the user to enter numbers into 3 different text boxes. When the user presses a button, the values in the textboxes should change as follows:

• The value in the first textbox should be replaced with the value from the third textbox
• The value in the 2nd textbox should be replaced with two times the value that was originally in the first textbox
• The value in the 3rd textbox should be replaced with three times the value that was originally in the 2nd textbox

HINT: You will need to use at least one variable.

For example if the following were the original values

After pressing the button once, the values should be changed to appear as follows:

After pressing the button a second time, the values should be changed to appear as follows:

etc ...

The purpose of this assignment is for you to get used to entering code with nested if/elseif/else statements.

Create a new VB project with the following interface:

The user of the program enters a number and presses the button. A series of different MessageBoxes will then be displayed. The contents of the message boxes depend on what number the user entered.

The code for the button's click handler can be seen by cliking here. The name of the button in the project is btnDoit and the name of the textbox is tbNum. IMPORTANT: When you type in the code, make SURE that you press ENTER after each time that you type the words THEN and ELSE. If you don't then VB will format the code in a different way than we learned about.

What messages boxes will be displayed when the user enters the following numbers?

• 1
• 3
• 40
• 55
• 72
• 73
• 74
• 81
• 100
• 200

Make sure that you are able to figure out the answers by just looking at the code. To check your answers you may try running the program and see what you get.

Question: Given the following code, what will the program display when the user clicks "Button1" ?

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim s As String
        Dim i, j As Integer
        j = 3
        For i = 2 To 4
            j = j + i * 2
            s = j.ToString() & j.ToString() & s
            MessageBox.Show(s)
        Next i
    End Sub

Write a program that asks the user to enter a number. The program should then compute the sum of "N + N/(N+1)" where N loops from 1 through the number that the user entered. For example, if the user enters the number 4 then the program should compute the following value and display the result (i.e. 12.716666):

(1 + 1/2) + (2 + 2/3) + (3 + 3/4) + (4 + 4/5)

= 12.716666666

Write a program that asks the user for a number. The program should then draw a vertical line of as many X's as the user specified. For example, if the user enters 4, the program should draw a vertical line of 4 X's:

X
X
X
X