memory and memory recall buttons for a calculator

Posted on 2000-02-22
Last Modified: 2012-05-04
I'm very new to programming and to visual basic 6.  I have made a calculator program and the code is as follows:

Option Explicit

Dim bDecimal As Boolean     ' Declares variable to create a flag for the decimal
Dim Op1, Op2                ' Previously input operand.
Dim NumOps As Integer       ' Number of operands.
Dim LastInput               ' Indicate type of last keypress event.
Dim OpFlag                  ' Indicate pending operation.
Dim TempOutput              ' Temporary storage

' Click event procedure for number keys (0-9).
' Append new number to the number in the display.

Private Sub cmdNumber_Click(index As Integer)
    If LastInput <> "NUMS" Then
        txtOutput.Text = Format(0, ".")
        bDecimal = False
    End If
    If bDecimal Then
        txtOutput.Text = txtOutput.Text + cmdNumber(index).Caption
        txtOutput.Text = Left(txtOutput.Text, InStr(txtOutput.Text, Format(0, ".")) - 1) + cmdNumber(index).Caption + Format(0, ".")
    End If
    If LastInput = "NEG" Then txtOutput.Text = "-" & txtOutput.Text
    LastInput = "NUMS"
End Sub

' If the immediately preceeding keypress was part of a
' number, increments NumOps. If one operand is present,
' set Op1. If two are present, set Op1 equal to the
' result of the operation on Op1 and the current
' input string, and display the result.

Private Sub cmdOperator_Click(index As Integer)
    TempOutput = txtOutput.Text
    If LastInput = "NUMS" Then
        NumOps = NumOps + 1
    End If
    Select Case NumOps
        Case 0
        If cmdOperator(index).Caption = "-" And LastInput <> "NEG" Then
            txtOutput.Text = "-" & txtOutput.Text
            LastInput = "NEG"
        End If
        Case 1
        Op1 = txtOutput.Text
        If cmdOperator(index).Caption = "-" And LastInput <> "NUMS" And OpFlag <> "=" Then
            txtOutput.Text = "-"
            LastInput = "NEG"
        End If
        Case 2
        Op2 = TempOutput
        Select Case OpFlag
            Case "+"
                Op1 = CDbl(Op1) + CDbl(Op2)
            Case "-"
                Op1 = CDbl(Op1) - CDbl(Op2)
            Case "*"
                Op1 = CDbl(Op1) * CDbl(Op2)
            Case "/"
                If Op2 = 0 Then
                   MsgBox "Can't divide by zero", 48, "Calculator"
                   Op1 = CDbl(Op1) / CDbl(Op2)
                End If
            Case "="
                Op1 = CDbl(Op2)
            Case "%"
                Op1 = CDbl(Op1) * CDbl(Op2)
            End Select
        txtOutput.Text = Op1
        NumOps = 1
    End Select
    If LastInput <> "NEG" Then
        LastInput = "OPS"
        OpFlag = cmdOperator(index).Caption
    End If
End Sub

' Reset the display and initializes variables.

Private Sub cmdCancel_Click()
    txtOutput = Format(0, "0")
    Op1 = 0
    Op2 = 0
End Sub

' Cancel last entry made

Private Sub cmdCancelEntry_Click()
    txtOutput.Text = Format(0, "0")
    bDecimal = False
    LastInput = "CE"
End Sub

' Will check to see if there is already a decimal
' if there is then the decimal is disabled

Private Sub cmdDecimal_Click()
If LastInput = "NEG" Then
        txtOutput.Text = Format(0, "-0.")
    ElseIf LastInput <> "NUMS" Then
        txtOutput.Text = Format(0, "0.")
    End If
    bDecimal = True
    LastInput = "NUMS"
End Sub

' Unload form

Private Sub cmdExit_Click()
End Sub

' Calculates the percent of txtOutput

Private Sub cmdPercent_Click()
    txtOutput.Text = txtOutput.Text / 100
    LastInput = "Ops"
    OpFlag = "%"
    NumOps = NumOps + 1
    bDecimal = True
End Sub

' Initialization routine for the form.
' Set all variables to initial values
' sets the flag to off when the form loads

Private Sub Form_Load()
bDecimal = False
NumOps = 0
LastInput = "NONE"
OpFlag = " "
txtOutput = Format(0, "0")
cmdDecimal.Caption = Format(0, ".")
End Sub

i need to have a memory button and a memory recall button.  Can someone please help me with the code for this.  Thanks in advance.

Question by:forbiddenR
  • 3
LVL 13

Expert Comment

ID: 2549590
you could use the save setting and getsetting command.

in the save button use
savesetting app.exename,"settings","memory",YourValue

then in the recall button


Author Comment

ID: 2551043
The simpler the better if at all possible.  I haven't been taught how to use the savesetting/getsetting command yet.  So I would like to use something that I understand and that would fit easily into my code.  Please and thank you.
LVL 13

Accepted Solution

crazyman earned 20 total points
ID: 2551143
If you wanted the value to remain in memory just as long as the calculator was running you could simply use a static variable to hold the current memory data and recall it when ever needed.

Private Sub SetMemory_Click()
    Memory "12345"
End Sub
Public Function Memory(Optional vNewVal As Variant) As Variant
    '''if a value is passed then the memory is changed
        ''' and new value returned
    '''otherwise the value is just returned
    Static vCurrentVal As Variant
    If Not IsMissing(vNewVal) Then vCurrentVal = vNewVal
    Memory = vCurrentVal
End Function

Private Sub GetMemory_Click()
    MsgBox Memory
End Sub

LVL 13

Expert Comment

ID: 2551169
You could of course just use a public variable which is probably the easiest way.

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