Home

Boolean Conjunctions and Disjunctions

Conditional Conjunctions

Nesting a Conditional Statement

In the body of the conditional statement, you can create another conditional statement. This is referred to as nesting the condition. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head runat="server">
<script runat="server">
Sub btnCalculateClick(ByVal sender As Object, ByVal e As EventArgs)
    Dim weeklySalary As Double
    Dim hourlySalary As Double
    Dim timeWorked As Double
    Dim overtime As Double
    Dim overtimePay As Double

    hourlySalary = CDbl(txtHourlySalary.Text)
    timeWorked = CDbl(txtTimeWorked.Text)
    weeklySalary = hourlySalary * timeWorked

    If chkPaidOvertime.Checked Then
        If timeWorked > 40.0 Then
            overtime = timeWorked - 40.0
            overtimePay = hourlySalary * 1.5 * overtime

            weeklySalary = (hourlySalary * 40.0) + overtimePay
        End If
    End If

    txtWeeklySalary.Text = FormatNumber(weeklySalary)
End Sub
</script>
<title>Payroll Preparation</title>
</head>
<body>
<form id="frmPayroll" runat="server">
<div>
<h3>Payroll Preparation</h3>

<table border=0>
  <tr>
    <td style="text-align: left">
        <asp:Label id="lblHourlySalary" runat="server" Text="Hourly Salary:"></asp:Label>
      </td>
    <td style="text-align: left">
        <asp:TextBox id="txtHourlySalary" Width="75px"
                                text="0.00" runat="server" /></td>
  </tr>
  <tr>
    <td style="text-align: left">
        <asp:Label id="lblTimeWorked" runat="server" Text="Time Worked:"></asp:Label></td>
    <td style="text-align: left">
        <asp:TextBox id="txtTimeWorked" text="0.00" runat="server" Width="75px" />
        </td>
  </tr>
    <tr>
    <td style="text-align: left">
        &nbsp;</td>
    <td style="text-align: left">
        <asp:CheckBox ID="chkPaidOvertime" runat="server" Text="Paid Overtime" />
        </td>
  </tr>
    <tr>
    <td style="text-align: left">
        &nbsp;</td>
    <td style="text-align: left">
        <asp:Button id="btnCalculate"
                              text="Calculate"
                              runat="server" OnClick="btnCalculateClick"></asp:Button></td>
  </tr>
    <tr>
    <td style="text-align: left">
        <asp:Label id="lblWeeklySalary" runat="server" Text="Weekly Salary:"></asp:Label></td>
    <td style="text-align: left">
        <asp:TextBox id="txtWeeklySalary" text="0.00" Width="75px" runat="server" /></td>
  </tr>
</table>
</div>
</form>
</body>
</html>

Here is an example of running the program:

Nesting a Conditional Statement
Nesting a Conditional Statement Nesting a Conditional Statement
Nesting a Conditional Statement Nesting a Conditional Statement

In the same way, you can nest one conditional statement in one, then nest that new one in another conditional statement, and so on.

Nesting the IIf() Function

To get the functionality of an If...Then...ElseIf... conditional statement, you can nest one IIf() function in another. In reality, you would call the IIf() function in place of the FalsePart of another IIf() function. The nesting can be presented as follows:

Function IIf(ByVal Expression As Boolean, 
             ByVal TruePart As Object,
             Function IIf(ByVal Expression As Boolean,
			  ByVal TruePart As Object,
			  Function IIf(ByVal Expression As Boolean,
				       ByVal TruePart As Object, 
				       Function IIf(ByVal Expression As Boolean,
						    ByVal TruePart As Object,
						    ByVal FalsePart As Object
				       ) As Object
			  ) As Object
	     ) As Object
) As Object

Only. Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head runat="server">
<script runat="server">
Sub btnCalculateClick(ByVal sender As Object, ByVal e As EventArgs)
    Dim periods = 0.00
    Dim principal = 0.00
    Dim futureValue = 0.00
    Dim interestRate = 0.00
    Dim interestEarned = 0.00
    Dim compoundFrequency = 0.00

    principal = txtPrincipal.Text
    interestRate = txtInterestRate.Text / 100.0
    periods = txtPeriods.Text

    compoundFrequency = IIf(ddlCompounded.Text = "Daily", 365, IIf(ddlCompounded.Text = "Weekly", 52.0, IIf(ddlCompounded.Text = "Monthly", 12.00, IIf(ddlCompounded.Text = "Quarterly", 4.00, IIf(ddlCompounded.Text = "Semiannually", 2.0, 1.00)))))

    futureValue = principal * Math.Pow((1.0 + (interestRate / compoundFrequency)), compoundFrequency * periods)
    interestEarned = futureValue - principal

    txtInterestEarned.Text = interestEarned
    txtFutureValue.Text = futureValue
End Sub
</script>
<style>
#container
{
    margin: auto;
    width:  355px;
}
#math {  width: 350px; }
</style>
<title>Compound Interest</title>
</head>
<body>
<form id="frmBusiness" runat="server">
<div id="math">

<h3>Compound Interest</h3>

<table id="estimation">
  <tr>
    <td><b>Principal:</b></td>
    <td><asp:TextBox id="txtPrincipal" style="width: 75px" runat="server"></asp:TextBox></td>
  </tr>
  <tr>
    <td><b>Interest Rate:</b></td>
    <td><asp:TextBox id="txtInterestRate" style="width: 55px;" runat="server"></asp:TextBox>%</td>
  </tr>
  <tr>
    <td><b>Periods:</b></td>
    <td><asp:TextBox id="txtPeriods" style="width: 55px;" runat="server"></asp:TextBox>Years</td>
  </tr>
  <tr>
    <td><b>Compounded:</b>
    </td>
    <td>
      <asp:DropDownList id="ddlCompounded" style="width: 120px;" runat="server">
        <asp:ListItem>Daily</asp:ListItem>
        <asp:ListItem>Weekly</asp:ListItem>
        <asp:ListItem>Monthly</asp:ListItem>
        <asp:ListItem>Quarterly</asp:ListItem>
        <asp:ListItem>Semiannually</asp:ListItem>
        <asp:ListItem>Annually</asp:ListItem>
      </asp:DropDownList>
        <asp:Button id="btnCalculate" Text="Calculate" OnClick="btnCalculateClick" runat="server" />
    </td>
  </tr>
  <tr>
    <td><b>Interest Earned:</b></td>
    <td><asp:TextBox id="txtInterestEarned" runat="server"></asp:TextBox></td>
  </tr>
  <tr>
      <td><b>Future Value:</b></td>
    <td><asp:TextBox id="txtFutureValue" runat="server"></asp:TextBox></td>
  </tr>
</table>
</div>
</form>
</body>
</html>

Here is an example of using the webpage:

Raising a Number to a Power

Raising a Number to a Power

Raising a Number to a Power

Boolean Conjunctions

When you nest one condition in another condition as in:

If condition1 = True	  ; The first or external condition
    If condition2 = True  ; The second or internal condition
	statement(s)
    End If
End If

you are in fact saying that "If condition1 verifies, Then if condition2 verifies, do this...". To support  a simplified version of this scenario, you can use the Boolean conjunction represented by the And operator. Its primary formula is:

condition1 And Condition2
    statement(s)

You must formulate each condition to produce a true or a false result. The result is as follows:

  • If condition1 is True AND condition2 is True, the whole expression produces a true result. Here is an example:
    <%@ Page Language="VB" %>
    
    <!DOCTYPE html>
    <html>
    <head runat="server">
    <script runat="server">
        Sub BtnCalculate_Click(ByVal sender As Object, ByVal e As EventArgs)
            Dim principal As Double, commission As Double
            Dim numberOfShares As Integer, pricePerShare As Double
    
            numberOfShares = CInt(TxtNumberOfShares.Text)
            pricePerShare = CDbl(TxtPricePerShare.Text)
    
            principal = numberOfShares * pricePerShare
    
            If principal >= 0.00 And principal <= 2500.00 Then
                commission = 26.25 + (principal * 0.0014)
            End If
            If principal > 2500.00 And principal <= 6000.00 Then
                commission = 45.0 + (principal * 0.0054)
            End If
            If principal > 6000.00 And principal <= 20000.00 Then
                commission = 60.0 + (principal * 0.0028)
            End If
            If principal > 20000.00 And principal <= 50000.00 Then
                commission = 75.0 + (principal * 0.001875)
            End If
            If principal > 50000.00 And principal <= 500000.00 Then
                commission = 131.25 + (principal * 0.0009)
            End If
            If (principal > 500000.0) Then
                commission = 206.25 + (principal * 0.000075)
            End If
    
            TxtPrincipal.Text = FormatNumber(principal)
            TxtCommission.Text = FormatNumber(commission)
            TxtTotalInvestment.Text = FormatNumber(principal + commission)
        End Sub
    </script>
    
    <style type="text/css">
    #main-title
    {
        font-size: 1.28em;
        font-weight: bold;
        text-align: center;
        font-family: Georgia, Garamond, 'Times New Roman', Times, serif;
    }
    #tblPayroll { width: 250px; }
    #whole
    {
        margin: auto;
        width:  255px;
    }
    </style>
    <title>Brokerage Company</title>
    </head>
    <body>
    <form id="frmBrokerage" runat="server">
    <div id="whole">
    <p id="main-title">Brokerage Company</p>
      
    <table id="tblPayroll">
      <tr>
          <td>
              <asp:Label id="LblNumberOfShares" runat="server"
              	     Text="Number of Shares:"></asp:Label>
          </td>
          <td><asp:TextBox id="TxtNumberOfShares" Width="75px"
                           runat="server">0</asp:TextBox></td>
        </tr>
        <tr>
          <td>
              <asp:Label id="LblPricePerShare" runat="server"
              	     Text="Price Per Share:"></asp:Label>
            </td>
          <td><asp:TextBox id="TxtPricePerShare" runat="server"
                           Width="75px">0.00</asp:TextBox></td>
        </tr>
        <tr>
          <td>&nbsp;</td>
          <td>
              <asp:Button id="BtnCalculate" runat="server"
                          Text="Calculate" Width="85px"
                          OnClick="BtnCalculate_Click" />
            </td>
        </tr>
        <tr>
          <td>
              <asp:Label id="LblPrincipal" runat="server" 
              		Text="Principal:"></asp:Label>
            </td>
          <td><asp:TextBox id="TxtPrincipal"
                           runat="server" Width="75px">0.00</asp:TextBox></td>
        </tr>
        <tr>
          <td>
              <asp:Label id="LblCommission" runat="server"
              			Text="Commission:"></asp:Label>
            </td>
          <td><asp:TextBox id="TxtCommission"
                           runat="server" Width="75px">0.00</asp:TextBox></td>
        </tr>
        <tr>
          <td>
              <asp:Label id="LblTotalInvestment" runat="server"
              	     Text="Total Investment:"></asp:Label>
            </td>
          <td><asp:TextBox id="TxtTotalInvestment" runat="server"
                           Width="75px">0.00</asp:TextBox>
          </td>
        </tr>
        </table>
    </div>
    </form>
    </body>
    </html>

    Here is an example of using the webpage:

    Boolean Conjunction

    Boolean Conjunction

  • If either condition1 or condition2 is false (including if both are false), the whole expression produces a false result

To make your code easier to read, it is a good idea to include each Boolean operation in its own parentheses. Here are examples:

<script runat="server">
Sub BtnCalculate_Click(ByVal sender As Object, ByVal e As EventArgs)
        Dim principal As Double, commission As Double
        Dim numberOfShares As Integer, pricePerShare As Double

        numberOfShares = CInt(TxtNumberOfShares.Text)
        pricePerShare = CDbl(TxtPricePerShare.Text)

        principal = numberOfShares * pricePerShare

        If (principal >= 0.00) And (principal <= 2500.00) Then
            commission = 26.25 + (principal * 0.0014)
        End If
        If (principal > 2500.00) And (principal <= 6000.00) Then
            commission = 45.0 + (principal * 0.0054)
        End If
        If (principal > 6000.00) And (principal <= 20000.00) Then
            commission = 60.0 + (principal * 0.0028)
        End If
        If (principal > 20000.00) And (principal <= 50000.00) Then
            commission = 75.0 + (principal * 0.001875)
        End If
        If (principal > 50000.00) And (principal <= 500000.00) Then
            commission = 131.25 + (principal * 0.0009)
        End If
        If (principal > 500000.0) Then
            commission = 206.25 + (principal * 0.000075)
        End If

        TxtPrincipal.Text = FormatNumber(principal)
        TxtCommission.Text = FormatNumber(commission)
        TxtTotalInvestment.Text = FormatNumber(principal + commission)
End Sub
</script>

Depending on your program, if two conditions are not enough, you can create as many conjunctions as you want. The formula to follow is:

condition1 And condition2 And condition3 And . . . And condition_n

When the expression is checked, if any of the operations is false, the whole operation is false. The only time the whole operation is true is if all of the operations are true.

Of course, you can nest a Boolean condition inside another conditional statement.

Short Circuiting a Conjunction

To provide a fast of performing conjunction, the Visual Basic language provides the AndAlso operator. The formula to use it is:

result = expression1 AndAlso expression2

The expressions are formulated as Boolean operations. The expression1 is first evaluated. If it is false, the operation is false. If the expression1 is true, then the expression2 is evaluated. If it is false, the result is false. If both expressions are true, then the result is true. Here are examples:

<script runat="server">
Sub btnCalculate_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim principal As Double, commission As Double
    Dim numberOfShares As Integer, pricePerShare As Double

    numberOfShares = If(String.IsNullOrEmpty(txtNumberOfShares.Text), 0, CInt(txtNumberOfShares.Text))
    pricePerShare = If(String.IsNullOrEmpty(txtPricePerShare.Text), 0.00, CDbl(txtPricePerShare.Text))

    principal = numberOfShares * pricePerShare

    If (principal >= 0.00) AndAlso (principal <= 2500.00) Then
        commission = 26.25 + (principal * 0.0014)
    End If

    If (principal > 2500.00) AndAlso (principal <= 6000.00) Then
        commission = 45.0 + (principal * 0.0054)
    End If

    If (principal > 6000.00) AndAlso (principal <= 20000.00) Then
        commission = 60.0 + (principal * 0.0028)
    End If

    If (principal > 20000.00) AndAlso (principal <= 50000.00) Then
        commission = 75.0 + (principal * 0.001875)
    End If

    If (principal > 50000.00) AndAlso (principal <= 500000.00) Then
        commission = 131.25 + (principal * 0.0009)
    End If

    If (principal > 500000.0) Then
        commission = 206.25 + (principal * 0.000075)
    End If

    txtPrincipal.Text = FormatNumber(principal)
    txtCommission.Text = FormatNumber(commission)
    txtTotalInvestment.Text = FormatNumber(principal + commission)
End Sub
</script>
 
 
 

Boolean Disjunctions

Introduction

A Boolean disjunction is a combination of conditions where only one of the conditions needs to be true for the whole operation to be true. This operation is performed using the Boolean disjunction operator represented as Or. The primary formula to follow is:

condition1 Or condition2

The operation works as follows:

  • If at least one of condition1 OR condition2 is true, the whole operation is true
  • If both conditions are false, only then will the whole operation produce a false result

Here is an example:

<%@ Page Language="VB" %>

<!DOCTYPE html>

<html>
<head runat="server">
<script runat="server">
Sub DdlTimePeriodSelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
    If ddlTimePeriod.SelectedIndex = 1 Or ddlTimePeriod.SelectedIndex = 2 Then
        pnlLunchSpecial.Visible = False
        pnlRegularMenu.Visible = True
    Else
        pnlLunchSpecial.Visible = True
        pnlRegularMenu.Visible = False
    End If
End Sub
</script>
<style type="text/css">
#main-title
{
    font-size: 1.28em;
    font-weight: bold;
    text-align: center;
    font-family: Georgia, Garamond, 'Times New Roman', Times, serif;
}
#tblRestaurant { width: 500px; }
#whole
{
    margin: auto;
    width:  505px;
}
</style>
<title>Restaurant</title>
</head>
<body>
<form id="frmRestaurant" runat="server">
<div id="whole">
 
<p id="main-title">Restaurant</p>

<table id="tblRestaurant">
  <tr>
    <td>
       <asp:Label id="lblTimePeriod" runat="server"
                  Text="Select Current Time Period:"></asp:Label>
    </td>
    <td>
       <asp:DropDownList id="ddlTimePeriod" runat="server"
                         AutoPostBack="True"
                         OnSelectedIndexChanged="ddlTimePeriodSelectedIndexChanged">
         <asp:ListItem>Weekday Lunch Period (11:30 AM - 03:00 PM)</asp:ListItem>
         <asp:ListItem>Evening (03:00 PM - Midnight)</asp:ListItem>
         <asp:ListItem>Weekend (Saturday - Sunday)</asp:ListItem>
      </asp:DropDownList>
    </td>
    </tr>
  </table>
  <asp:Panel id="pnlLunchSpecial" runat="server" Width="400px">
    <h2>Lunch Special</h2>
    <table class="auto-style1">
      <tr>
        <td>Food Item</td>
        <td>Unit Price</td>
        <td>Spicy?</td>
      </tr>
        <tr>
          <td>
             <asp:Label id="lblLSItem1Name" runat="server"
                        Text="LS01 Chicken Chow Mein"></asp:Label>
          </td>
          <td>
             <asp:TextBox id="txtLSItem1UnitPrice"
                          runat="server" Width="70px">5.65</asp:TextBox>
          </td>
          <td>
                        <asp:CheckBox id="chkLSItem1Spicy" runat="server" />
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Label id="lblLSItem2Name" runat="server"
                                   Text="LS02 Sweet &amp; Sour Pork"></asp:Label>
                    </td>
                    <td>
                        <asp:TextBox id="TxtLSItem2UnitPrice" runat="server"
                                             Width="70px">5.75</asp:TextBox>
                    </td>
                    <td>
                        <asp:CheckBox id="chkLSItem2Spicy" Checked="True" runat="server" />
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Label id="lblLSItem3Name" runat="server"
                                         Text="LS03 Sesame Chicken"></asp:Label>
                    </td>
                    <td>
                        <asp:TextBox id="txtLSItem3UnitPrice" runat="server"
                                     Width="70px">5.85</asp:TextBox>
                    </td>
                    <td>
                        <asp:CheckBox id="chkLSItem3Spicy" Checked="True" runat="server" />
                    </td>
                </tr>
            </table>
        </asp:Panel>

        <asp:Panel id="PnlRegularMenu" runat="server" Width="400px" Visible="False">
            <h1>Regular Food Menu</h1>
            <table class="auto-style1">
                <tr>
                    <td>Food Item</td>
                    <td>Unit Price</td>
                    <td>Spicy?</td>
                </tr>
                <tr>
                    <td>
                        <asp:Label id="lblRMItem1Name" runat="server"
                                   Text="RM01 Chicken Mei Fun"></asp:Label>
                    </td>
                    <td>
                        <asp:TextBox id="txtRMItem1UnitPrice" runat="server"
                                     Width="70px">9.25</asp:TextBox>
                    </td>
                    <td>
                        <asp:CheckBox id="chkRMItem1Spicy" runat="server" />
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Label id="lblRMItem2Name" runat="server"
                                   Text="RM02 Orange Chicken"></asp:Label>
                    </td>
                    <td>
                        <asp:TextBox id="txtRMItem2UnitPrice" runat="server"
                                     Width="70px">9.50</asp:TextBox>
                    </td>
                    <td>
                        <asp:CheckBox id="chkRMItem2Spicy" runat="server" />
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Label id="lblRMItem3Name" runat="server"
                                   Text="RM03 Barbecue Spare Ribs"></asp:Label>
                    </td>
                    <td>
                        <asp:TextBox id="txtRMItem3UnitPrice" runat="server"
                                     Width="70px">14.65</asp:TextBox>
                    </td>
                    <td>
                        <asp:CheckBox id="chkRMItem3Spicy" Checked="True" runat="server" />
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Label id="lblRMItem4Name" runat="server"
                                   Text="Chicken Chow Mein "></asp:Label>
                    </td>
                    <td>
                        <asp:TextBox id="TextBox1" runat="server"
                                     Width="70px">12.25</asp:TextBox>
                    </td>
                    <td>
                        <asp:CheckBox id="chkRMItem4Spicy" Checked="True" runat="server" />
                    </td>
                </tr>
        </table>
    </asp:Panel>
</div>
</form>
</body>
</html>

Here is an example of using the webpage:

Boolean Disjunctions

Boolean Disjunctions

It is a good idea to include each Boolean operation in its parentheses. Here is an example:

<script runat="server">
Sub DdlTimePeriodSelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
    If  (ddlTimePeriod.SelectedIndex = 1) Or (ddlTimePeriod.SelectedIndex = 2) Then
        pnlLunchSpecial.Visible = False
        pnlRegularMenu.Visible = True
    Else
        pnlLunchSpecial.Visible = True
        pnlRegularMenu.Visible = False
    End If
End Sub
</script>

You can create a conditional statement that includes as many disjunctions as you want. The formula to follow is:

condition1 Or condition2 Or . . . Or condition_n

If any one of the individual operations is true, the whole operation is true. The whole operation is false only if all of the operations are false.

Short-Cicuiting a Disjunction

To provide a fast way to perform a disjunction, the Visual Basic language provides the OrElse operator. The formula to use it is:

result = expression1 OrElse expression2

The expressions are evaluated as done for the regular disjunction.

Combining Conjunctions and Disjunctions

Conjunctions and disjunctions can be used in the same expression. A conjunction (or disjunction) can be used to evaluate one sub-expression while a disjunction (or conjunction) can be used to evaluate another sub-expression.

As seen previously, one way you can combine conditional statements is by nesting them.

 
 
   
 

Previous Copyright © 2008-2016, FunctionX Next