meljun cortes itc 22 midterm exercises

7/27/2019 MELJUN CORTES ITC 22 Midterm Exercises

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JOSE RIZAL UNIVERSITY Computer Science Department

ITC 22 Database Management Systems

LABORATORY EXERCISES

MIDTERM PERIOD

SAMPLE EXERCISE #1Building a Visual Basic Application

Launch Microsoft Visual Basic.

Create the Source Code Window, producing the output below:

Figure 2.1 Source Code Window

Visualize the List of Objects:

Figure 2.2: List of Objects

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Visualize the List of Objects:

Figure 2.3: List of Procedures

Key in the lines in between the above two statements.

Private Sub Form_Load ( )Form1.showPrint Welcome to Visual Basic tutorial

End Sub

Run the program, press F5 or click on the run button to run the program.

SAMPLE EXERCISE #2

Simple Arithmetic Calculations

Perform simple arithmetic calculations as shown in example 2.1.2. VB uses * to denote the

multiplication operator and / to denote the division operator.

The output is shown in figure 2.3, where the results are arranged vertically.

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Use the ff. Source Code:

Private Sub Form_Activate ( )Print 20 + 10Print 20 - 10Print 20 * 10Print 20 / 10

End Sub

Use the ff. Source Code for another set:

Private Sub Form_Activate ( )x = 20y = 10Print x + yPrint x - yPrint x * yPrint x / y

End Sub

SAMPLE EXERCISE #3

Besides, you can also use the + or the & operator to join two or more texts (string) together like

in example 2.1.4 (a) and (b)

Private Sub Form_Activate( )A = "Tom"B = likes"C = to"D = eat"E = burger"Print A + + B + + C + + D + + E

End Sub

Sample Exercise #4Private Sub cmdnext_Click()

Form2.Show

Form1.HideEnd Sub

Private Sub Form_Activate()Print "Welcome to VB"

End Sub

Private Sub cmdexit_Click()End

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End Sub

Private Sub Form_Activate()

Print "VB is fun and easy"End Sub

SAMPLE EXERCISE #5

Introduction to Programming Concept (OOP)

The procedure to calculate and to display the output on the label is shown below. The output is

shown in Figure 3.1.

Objects/Controls Name Text Event /Procedure

Form1 Form1 None Load

Label1 lblNum1 Number 1 NoneLabel2 lblNum2 Number 2 None

Label3 lblAnswer Answer None

TextBox1 txtNum1 None None

TextBox2 txtNum2 None None

TextBox3 txtNum3 None NoneCommandButton1 CmdSum Addition Click

CommandButton2 CmdClear Clear Click

Code:

Dim num1,num2,result As IntegerPrivate Sub cmdSum_Click()num1 = Val(txtNum1.Text)num2 = Val(txtNum2.Text)result = numb1 + num2txtNum3.Text = result

End Sub

Private Sub cmdclear_Click()txtNum1.Text = ""txtNum2.Text = ""

txtNum3.Text = ""End Sub

GRADED EXERCISE #1 LASTNAMEEXER1

Introduction to Programming Concept (OOP)

1. Modify the calculator program (EXERCISE#1) by allowing the user to select from any of the

four fundamental operations and display the correct answer.

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Dim a,b,c As IntegerPrivate Sub cmdSum_Click()

a = Val(txtNum1.Text)b = Val(txtNum2.Text)c = a + btxtNum3.Text = c

End Sub

Private Sub cmdclear_Click()txt1.Text = ""txt2.Text = ""txt3.Text = ""

End Sub

Private Sub cmddiv_Click()a = Val(txt1.Text)b = Val(txt2.Text)c = a / btxt3.Text = c

End Sub

Private Sub cmdexit_Click()End

End Sub

Private Sub cmdmul_Click()a = Val(txt1.Text)b = Val(txt2.Text)c = a * btxt3.Text = c

End Sub

Private Sub cmdsub_Click()a = Val(txt1.Text)b = Val(txt2.Text)c = a - btxt3.Text = c

End Sub

GRADED EXERCISE 2 LASTNAMEEXER2

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2. Write a program that will input three different integers and print the sum, the average, and the

product of these numbers. Provide an Exit button to terminate program execution.

Dim num1, num2, num3, sum, prod As Integer

Dim ave As Double

Private Sub cmdAve_Click()

num1 = Val(txt1.Text)


num3 = Val(txt3.Text)ave = (num1 + num2 + num3) / 3

txt4.Text = ave

End Sub

Private Sub cmdclear_Click()

txt1.Text = ""txt2.Text = ""

txt3.Text = ""

txt4.Text = ""End Sub

Private Sub cmdexit_Click()

EndEnd Sub

Private Sub cmdprod_Click()num1 = Val(txt1.Text)


num3 = Val(txt3.Text)prod = num1 * num2 * num3

txt4.Text = prod

End Sub

Private Sub cmdsum_Click()



num3 = Val(txt3.Text)sum = (num1 + num2 + num3)

txt4.Text = sumEnd Sub


3. Write a temperature conversion program that converts a Fahrenheit temperature to a Celsius

temperature. Provide a Textbox for user input and another Textbox for displaying the converted

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temperature. Also provide the user with an Exit button to end program execution. Use the

following formula: Celsius 5 / 9 * (Fahrenheit 32).


4. Write a program that reads in the radius of a circle as an integer and prints the circles diameter,circumference and area. Provide textboxes for each of these calculations. Use the following

formulas:

diameter = 2 * radius

circumference = 2 * 3.1415 * radiusarea = 3.1415 * radius * radius

PRACTICE EXERCISE #2

Control Structures in VB 6.0

Data-Entry Validation Problem Using Multiple If/Then/Else Structure

1. Create an application that will validate a value entered. If the value is between 100 and 200 then the value

is accepted. Otherwise rejected.

Object Property Settings

Form Name frmValidate

Caption Validation

Textbox Name txtEntry

Text None

TabIndex 0

Button Name cmdAcceptCaption Accept

Enabled False

Code:

Private Sub cmdAccept_Click( )

Dim Valuentry As Integer

ValueEntry = val(txtEntry.Text)

If (ValueEntry >= 100) Then

msgbox Entry Accepted

ElseIf (ValueEntry > 200) Then

msgbox Invalid

EndIf

EndIf

End Sub

The preceding code seems to be the right code for the problem. In fact, there is no error when you

compile the program. Unfortunately, the code always revert to true whenever the input is greater than

100 rendering the code after the else statement useless. Lets modify the code:

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Private Sub cmdAccept_Click( )

Dim Valuentry As IntegerValueEntry = val(txtEntry.Text)

If (ValueEntry >= 100) And (ValueEntry < 200) Then

msgbox Entry AcceptedElse

msgbox Invalid

EndIf

End Sub

Private Sub txtEntry_change( )

cmdAccept.Enabled = True

End Sub

2. Compute for the Gross Pay wherein the formula is HoursWorked multiplied to Rate per hour only if the

number of hours worked is less than or equal to 40 hours. Otherwise, an hours in excess of 40 is 1.5 therate per hour.


Form Name FrmPayroll

Caption Simple Payroll

Textbox Name txtHoursWorked

Text

Textbox Name txtRate

Text

Textbox Name txtOTHours

Text

Textbox Name txtOTpay

Text

Textbox Name txtBasicPay

Text

Textbox Name txtGrossPay

Text

Label Name lblHours

Caption Hours Worked

Label Name lblRate

Caption Rate

Label Name lblOTHours

Caption OT HoursLabel Name lblOTPay

Caption OT Pay

Label Name lblBasicPay

Caption Basic Pay

Label Name lblGrossPay

Caption Gross Pay

Button Name cmdCompute

Code:

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Private Sub cmdCompute_Click()

Dim Rate, HoursWorked, OTHours, OTPay, Basic, Gross As Integer

Rate = Val(txtRate.Text)HoursWorked = Val(txtHoursWorked.Text)

OTHours = Val(txtOTHours.Text)OTPay = Val(txtOTPay.Text)

Basic = Val(txtBasicPay.Text)

Gross = Val(txtGrossPay.Text)

If (HoursWorked 40) ThenOTHours = HoursWorked 40

OTPay = Rate * OTHours * 1.5

Basic = Rate * 40

Gross = Basic + OTPay

txtOTHours.Text = OTHours

txtOTPay.Text = OTPay

txtBasicPay.Text = BasictxtGrossPay.Text = Gross

End If

End If

End Sub


Using ListBox and ComboBox Controls In Visual Basic 6

1. Open a new Standard EXE project is opened an named the Form as Listbox.frm and save the

project as Listbox.vbp2. Design the application as shown below.


Form Caption

Name

ListBox

frmListBox

TextBoxText

Name

(empty)

TxtName

Label

Caption Enter a name

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Name lblName

ListBox Name FirstName

LabelCaption

Name

Amount Entered

lblAmount

Label

Caption

Name

Border Style

(empty)

lblDisplay

1 Fixed Single

CommandButton Caption

Name

Add

cmdAdd

CommandButtonCaption

Name

Remove

cmdRemove


Name

Clear

cmdClear


Name

Exit

cmdExit

3. The following event procedures are entered for the TextBox and CommandButton controls.

Private Sub txtName_Change()If (Len(txtName.Text) > 0) Then 'Enabling the Add button'if atleast one character

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'is enteredcmdAdd.Enabled = TrueEnd If

End Sub

Private Sub cmdAdd_Click()lstName.AddItem txtName.Text 'Add the entered the characters to the list boxtxtName.Text = "" 'Clearing the text box

txtName.SetFocus 'Get the focus back to the'text box

lblDisplay.Caption = lstName.ListCount 'Display the number of items in the list box

cmdAdd.Enabled = False ' Disabling the Add button

End Sub

4. The click event of the Add button adds the text to the list box that was typed in the Text box.Then the text box is cleared and the focus is got to the text box. The number of entered values

will is increased according to the number of items added to the listbox.

Private Sub cmdClear_Click()lstName.ClearlblDisplay.Caption = lstName.ListCountEnd Sub

Private Sub cmdExit_Click()Unload MeEnd Sub

Private Sub cmdRemove_Click()Dim remove As Integer

remove = lstName.ListIndex 'Getting the index

If remove >= 0 Then 'make sure an item is selected'in the list box

lstName.RemoveItem remove 'Remove item from the list box

lblDisplay.Caption = lstName.ListCount 'Display the number of items'in the listbox

End If

End Sub

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1. The following example illustrates the use of CheckBox control

2. Open a new Project and save the Form as CheckBox.frm and save the Project asCheckBox.vbp

3. DDesign the Form as shown below

Object Property Setting

FormCaption

Name

CheckBox

frmCheckBox

CheckBoxCaption

Name

Bold

ChkBold

CheckBoxCaption

Name

Italic

ChkItalic

CheckBoxCaption

Name

Underline

ChkUnderline

OptionButtonCaption

Name

Red

OptRed

OptionButtonCaption

Name

Blue

OptBlue

OptionButtonCaption

Name

Green

OptGreen

TextBoxName

Text

TxtDisplay

(empty)


Name

Exit

CmdExit

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4. Following code is typed in the Click() events of the CheckBoxes

Private Sub chkBold_Click()If chkBold.Value = 1 ThentxtDisplay.FontBold = True

ElsetxtDisplay.FontBold = False

End IfEnd Sub

Private Sub chkItalic_Click()If chkItalic.Value = 1 ThentxtDisplay.FontItalic = True

Else

txtDisplay.FontItalic = FalseEnd IfEnd Sub

Private Sub chkUnderline_Click()

If chkUnderline.Value = 1 ThentxtDisplay.FontUnderline = True

ElsetxtDisplay.FontUnderline = False

End If

End Sub

Following code is typed in the Click() events of the OptionButtons

Private Sub optBlue_Click()txtDisplay.ForeColor = vbBlue

End Sub

Private Sub optRed_Click()

txtDisplay.ForeColor = vbRed

End Sub

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Private Sub optGreen_Click()

txtDisplay.ForeColor = vbGreenEnd Sub

To terminate the program following code is typed in the Click() event of the Exit button

Private Sub cmdExit_Click()End

End Sub

5. Run the program by pressing F5. Check the program by clicking on OptionButtons and

CheckBoxes.



1. Open a new Standard EXE project and the save the Form as Option.frm and save the project as

Option.vbp.

Design the Form as per the following specifications table.


LabelCaption

Name

Enter a Number

Label1

TextBoxText

Name

(empty)

Text1


Name

&Close

Command1

OptionButtonCaption

Name

&Octal

OptOct

OptionButtonCaption

Name

&Hexadecimal

OptHex

OptionButtonCaption

Name

&Decimal

OptDec

The application responds to the following events.

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The change event of the TextBox reads the value and stores it in a form-level numeric variable.

The click event of optOct button returns curretval in octal.

The click event of the optHex button curerntval in hexadecimal The click event of the optDec button returns the decimal equivalent of the value held currentval.

The following code is entered in the general declarations section of the Form.

Dim currentval as variant

The variable is initialized to 0 by default. The change event procedure checks to ascertain the

number system (Octal, Hexadecimal) that is in effect and then reads in the number.

Private Sub Text1_Change()

If optOct.Value = True Thencurrentval = Val ("&O" & LTrim (Text1.Text) & "&")Elseif optDec.value = True Thencurrentval = Val (LTrim (Text1.Text) & "&")Elsecurrentval = Val ("&H" & LTrim (Text1.Text) & "&")End ifEnd Sub

The Val function is used to translate string to a number and can recognize Octal and Hexadecimal

strings. The LTrim function trims the leading blanks in the text. The following code is entered in theclick events of the OptionButton controls.

Private Sub optOct_Click()Text1.Text = Oct(currentval)End Sub

Private Sub optHex_Click()Text1.Text = Hex(currentval)End Sub

Private Sub optDec_Click()Text1.Text = Format(currentval)End Sub

The following code is entered in the click event of the Close button.

Private Sub cmdClose_Click()

Unlod MeEnd Sub



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1. Open a new Project and save the Form as messageboxdemo.frm and save the Project as

messageboxdemo.vbp

2. Design the application as shown below.Object Property Setting

Form

Caption

Name

MessageBoxDemo

frmMessageBoxDemo

Label

Caption

Name

lblName

Name

TextBox Name

Text

txtName

( empty )

ListBox Name LstName

CommandButton

Caption

Name

Add

CmdAdd

CommandButton

Caption

Name

Delete

CmdDelete

CommandButton

Caption

Name

Exit

CmdExit

3. Following code is entered in the txtName_Change ( ) event.

Private Sub txtName_Change()If Len(txtName.Text) > 0 Then

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cmdAdd.Enabled = TrueEnd IfEnd Sub

4. Following code has to be entered in the cmdAdd_Click ( ) event.

Private Sub cmdAdd_Click()answer = MsgBox("Do you want to add this name to the list box?", vbExclamation +vbYesNo,"Add Confirm")If answer = vbYes ThenlstName.AddItem txtName.TexttxtName.Text = ""txtName.SetFocuscmdAdd.Enabled = FalseEnd IfEnd Sub

Following code is entered in the cmdDelete_Click ( ) event

Private Sub cmdDelete_Click()Dim remove As Integerremove = lstName.ListIndexIf remove < 0 ThenMsgBox "No names is selected", vbInformation, "Error"Elseanswer = MsgBox("Are you sure you want to delete " & vbCrLf & "the selected name?",_vbCritical + vbYesNo, "Warning")If answer = vbYes ThenIf remove >= 0 ThenlstName.RemoveItem removetxtName.SetFocusMsgBox "Selected name was deleted", vbInformation, "Delete Confirm"

End IfEnd IfEnd IfEnd Sub

5. Following code is entered in the cmdExit_Click ( ) event

Private Sub cmdExit_Click()answer = MsgBox("Do you want to quit?", vbExclamation + vbYesNo, "Confirm")If answer = vbYes ThenEndElseMsgBox "Action canceled", vbInformation, "Confirm"

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End IfEnd Sub

6. Save and run the application. You can notice the different type of message box types are used toperform an action.



1. Open a new project and save the Form as InputBox.frm and save the Project as InputBox.vbp

2. Design the application as shown below.

Object Property Setting

Form

Caption

Name

InputBox test

FrmInputBox

Label

Caption

Name

You entered

lbl1

Label

Caption

Name

BorderStyle

( empty)

lbl2

1-FixedSingle

CommandButton

Caption

Name

OK

cmdOK

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3. Following code is entered in cmdOK_Click ( ) event

Private Sub cmdok_Click()Dim ans As Stringans = InputBox("Enter something to be displayed in the label", "Testing", 0)If ans = "" Thenlbl2.Caption = "No message"Elselbl2.Caption = ansEnd IfEnd Sub

4. Save and run the application. As soon as you click the OK button you will get the following

InputBox

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Using Select Case, ListBox and ComboBox Controls In Visual Basic 6

1. Genetic Computer Institute wants to install a security keypad outside a laboratory room. Only

authorized personnel may enter the laboratory using their security codes. The following are valid

and authorized codes:a. 2001 2003 Technicians

b. 2004 2009 Marketing Services

c. 2010 2015 Lecturersd. 2016 2020 Managers

2. Write a security program that accepts only the following codes using Select Case statement.

3. Write a program that displays the names of cities in Metro Manila in a ComboBox. When anitem is selected from the ComboBox remove it.

4. Modify your solution in #1. When the user selects an item from the ComboBox, remove the item

from the ComboBox and add it to the ListBox.

5. Write a program that will allow the user to type the text in a textbox and transfer it to the Listbox

and clear the textbox. In case the inputted text needs correction, the user should be able to selectthe item and return it in the textbox for correction and then back again.

6. Write a program that allows the user to enter a series of values in a Listbox to be translated intoFahrenheit or Celsius temperatures. When the user selects one of the items in the listbox, the

program has button options to translate the item into Celsius or Fahrenheit degree.

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meljun cortes itc 22 midterm exercises

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