Computer Science

Submit to your professor a MS Word document with replies to the following questions (keep the question’s text before each of your replies).

1. Determine whether the condition is true or false. Assume a = 2 and b = 3.

((a = b) Or Not (b < a)) And ((a < b) Or (b = a + 1))

2. Determine whether or not the two conditions are equivalent - that is, whether they will be true or false for exactly the same values of the variables appearing in them.

Not ((a = b) Or (a = c)); (a <> b) And (a <> c)

3. Determine the output displayed in the text box when the button is clicked.  Assume the response is B

Private Sub btnDisplay_Click(...) Handles btnDisplay.Click

Dim letter As String

letter = InputBox("Enter A, B, or C.")

letter = letter.ToUpper

If letter = "A" Then

txtOutput.Text = "A, my name is Alice."

ElseIf letter = "B" Then

txtOutput.Text = "To be, or not to be."

ElseIf letter = "C" Then

txtOutput.Text = "Oh, say, can you see."

Else

txtOutput.Text = "Not a valid letter."

End If

End Sub

4. Identify the errors.

Private Sub btnDisplay_Click(...) Handles btnDisplay.Click

'Is your program correct?

Dim query, answer1, answer2 As String

query = "Are you sure everything in your program is correct?"

answer1 = InputBox(query)

answer1 = answer1.ToUpper.Substring(0, 1)

If answer1 = "N" Then

txtOutput.Text = "Don't patch bad code, rewrite it."

Else

query = "Does your program run correctly?"

answer2 = InputBox(query)

answer2 = answer2.ToUpper.Substring(0, 1)

If answer2 = "Y" Then

txtOutput.Text = "Congratulations."

Else

txtOutput.Text = "Something you are sure about is wrong."

End If

End Sub

5. The current calendar, called the Gregorian calendar, was introduced in 1582. Every year divisible by four was declared to be a leap year, with the exception of the years ending in 00 (that is those divisible by 100) and not divisible by 400. For instance, the years 1600 and 2000 are leap years, but 1700, 1800, and 1900 are not. Write a program that requests a year as input and states whether it is a leap year. (Test the program on the years 2008, 2009, 1900, and 2000.)

6. For each of the responses shown in the parentheses, determine the output displayed in the text box when the button is clicked.

Private Sub btnDisplay_Click(...) Handles btnDisplay.Click

Dim yearENIAC As Integer

'Ask question and obtain answer

Dim message As String

message = "In what year was the ENIAC computer completed?"

yearENIAC = CInt(InputBox(message))

'Respond to answer

Select Case yearENIAC

Case 1945

txtOutput.Text = "Correct."

Case 1943 To 1947

txtOutput.Text = "Close, 1945."

Case Is < 1943

txtOutput.Text = "Sorry, 1945. Work on the ENIAC " & _

"began in June 1943."

Case Is > 1947

txtOutput.Text = "No, 1945. By then IBM had built " & _

"a stored-program computer."

End Select

End Sub

(1940, 1945, 1950)

7. Rewrite the code using a Select Case block.

If a = 1 Then

lstOutput.Items.Add("lambs")

End If

If ((a <= 3) And (a < 4)) Then

lstOutput.Items.Add("eat")

End If

If ((a = 5) Or (a > 7)) Then

lstOutput.Items.Add("ivy")

End If