Full Calculator Project (Visual Basic Tutorial - 7)

Create a form with      1 text boxe , 1 Label , And 24 command buttons.

Text box properties…………..

Named: txtDisplay

Alignment: 1-Right Justify

Enabled: False

Text: 0

Command buttons properties…………..

Command buttons 1 - Name: cmdAllClear

                                    Capuion: AC

Command buttons 2 - Name: cmdClear

                                    Capuion: C

Command buttons 3 - Name: cmdSquareRoot

                                    Capuion: Sqrt

Command buttons 4 - Name: cmdPercent

                                    Capuion: %

Command buttons 5 - Name: cmdOperatort

                                    Capuion: /

                                    Index: 0

Command buttons 6 - Name: cmdMemoryClear

                                    Capuion: MC

Command buttons 7 - Name: cmdNumber

                                    Capuion: 7

                                    Index: 6

Command buttons 8 - Name: cmdNumber

                                    Capuion: 8

                                    Index: 7

Command buttons 9 - Name: cmdNumbert

                                    Capuion: 9

                                    Index: 8

Command buttons 10 - Name: cmdOperato

                                    Capuion: *

                                    Index: 1

Command buttons 11 - Name: cmdMemoryReminder

                                    Capuion: MR

Command buttons 12 - Name: cmdNumber

                                    Capuion: 4

Index: 3

Command buttons 13 - Name: cmdNumber

                                    Capuion: 5

                                    Index: 4

Command buttons 14 - Name: cmdNumber

                                    Capuion: 6

                                    Index: 5

Command buttons 15 - Name: cmdOperator

                                    Capuion: -

                                    Index: 2

Command buttons 16 - Name: cmdMemoryPlus

                                    Capuion: M+

Command buttons 17 - Name: cmdNumber

                                    Capuion: 1

                                    Index: 0

Command buttons 18 - Name: cmdNumbert

                                    Capuion: 2

                                    Index: 1

Command buttons 19 - Name: cmdNumber

                                    Capuion: 3

                                    Index: 2

Command buttons 20 - Name: cmdOperator

                                    Capuion: +

                                    Index: 3

Command buttons 21 - Name: cmdMemoryMinus

                                    Capuion: M-

Command buttons 22 - Name: cmdNumber

                                    Capuion: 0

                                    Index: 9

Command buttons 23 - Name: cmdPoint

                                    Capuion: .

Command buttons 24 - Name: cmdEqual

                                    Capuion: =.

Add the following code to the form code module for the ‘frmCalculator’ _Click event:

Program code:

Dim FirstNumber As Double

Dim LastNumber As Double

Dim Operator As String

Dim ClearDisplay As Boolean

Dim Result As Double

Dim Memory As Double

Private Sub cmdAllClear_Click()

txtDisplay.Text = "0"

Operator = ""

FirstNumber = 0

LastNumber = 0

ClearDisplay = False

Result = 0

End Sub

Private Sub cmdClear_Click()

txtDisplay.Text = "0"

End Sub

Private Sub cmdEqual_Click()

'sets the value of the variable "LastNumber"

LastNumber = Val(txtDisplay.Text)

'it exits if no operator was pressed before

If Operator = "" Then Exit Sub

'checks which operator was pressed

'then calculates the result accordingly to that operator

If Operator = "+" Then Result = FirstNumber + LastNumber

If Operator = "-" Then Result = FirstNumber - LastNumber

If Operator = "*" Then Result = FirstNumber * LastNumber

If Operator = "/" Then

    'shows an error messege if the division number=0

    'otherwise calculates the result

    If LastNumber = 0 Then

        txtDisplay.Text = "Error: Positive Infinity"

        ClearDisplay = True

        Exit Sub

    Else

        Result = FirstNumber / LastNumber

    End If

End If

'shows the result in the Display Box

txtDisplay.Text = Str(Result)

ClearDisplay = True

Operator = ""

End Sub

Private Sub cmdMemoryClear_Click()

Memory = 0

lblMemory.Caption = ""

ClearDisplay = True

End Sub

Private Sub cmdMemoryMinus_Click()

Memory = Memory - Val(txtDisplay.Text)

lblMemory.Caption = "M"

ClearDisplay = True

End Sub

Private Sub cmdMemoryPlus_Click()

Memory = Memory + Val(txtDisplay.Text)

lblMemory.Caption = "M"

ClearDisplay = True

End Sub

Private Sub cmdMemoryReminder_Click()

txtDisplay.Text = Str(Memory)

ClearDisplay = True

End Sub

Private Sub cmdNumber_Click(Index As Integer)

'if any operator is pressed or newly starts calculating,

'the Display box will be cleared

If ClearDisplay = True Then txtDisplay.Text = ""

'clears the Display box if it shows only "0" because

'"0" cannot be the first digit of a whole number

If txtDisplay.Text = "0" Then txtDisplay.Text = ""

'writes the number that is shown on the button

txtDisplay.Text = txtDisplay.Text & cmdNumber(Index).Caption

'sets the value "False" or the variable ClearDisplay

ClearDisplay = False

End Sub

Private Sub cmdOperator_Click(Index As Integer)

'sets the value of the variable "FirstNumber"

FirstNumber = Val(txtDisplay.Text)

'sets which operator is pressed

Operator = cmdOperator(Index).Caption

'sets cleardisplay to "False"

ClearDisplay = True

End Sub

Private Sub cmdPoint_Click()

'if the point button is pressed after pressing any operator

'it starts a new decimal number

If ClearDisplay = True Then

    txtDisplay.Text = "0."

    ClearDisplay = False

End If

'checks if there is any point in the number in the txtDisplay

'if no point found it sets a new point

If InStr(txtDisplay.Text, ".") = 0 Then

    txtDisplay.Text = txtDisplay.Text & "."

    ClearDisplay = False

End If

End Sub

Private Sub cmdSquareRoot_Click()

'shows an error messege if it is a negative number

'otherwise calculates the squareroot value of the number

If Val(txtDisplay.Text) >= 0 Then

    txtDisplay.Text = Sqr(Val(txtDisplay.Text))

Else

    txtDisplay.Text = "Invalid Input for Function"

End If

ClearDisplay = True

End Sub

Private Sub Form_Load()

Top = (Screen.Height - Height) / 2

Left = (Screen.Width - Widht) / 3

End Sub

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Download this Calculator Project File  click hare 14 kb

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