My app functions, but when I enter 1 democrats, the totals show 3 Dem, 1 Rep, an
ID: 3702337 • Letter: M
Question
My app functions, but when I enter 1 democrats, the totals show 3 Dem, 1 Rep, and 1 Indep.
What's wrong with my array? here is the code:
Public Class FrmMain
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Me.Close()
End Sub
Private Sub FrmMain_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
lstparty.Items.Add("D")
lstparty.Items.Add("R")
lstparty.Items.Add("I")
lstparty.SelectedIndex = 0
End Sub
Private Sub txtAge_KeyPress(sender As Object, e As KeyPressEventArgs) Handles txtAge.KeyPress
If (e.KeyChar < "0" OrElse e.KeyChar > "9") AndAlso
e.KeyChar <> ControlChars.Back Then
e.Handled = True
End If
End Sub
Private Sub btnWrite_Click(sender As Object, e As EventArgs) Handles btnWrite.Click
Dim outFile As IO.StreamWriter
If txtAge.Text <> String.Empty Then
outFile = IO.File.AppendText("pao.txt")
outFile.WriteLine(lstParty.SelectedItem.ToString)
outFile.WriteLine(txtAge.Text)
outFile.Close()
End If
End Sub
Private Sub btnTotals_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnTotals.Click
Dim strParty As String
Dim strAge As String
Dim inFile As IO.StreamReader
Dim intTotalDem As Integer
Dim intTotalRep As Integer
Dim intTotalInd As Integer
If IO.File.Exists("pao.txt") = True Then
inFile = IO.File.OpenText("pao.txt")
Do Until inFile.Peek() = -1
strParty = inFile.ReadLine
strAge = inFile.ReadLine
If strParty = "D" Then
intTotalDem += 1
ElseIf strParty = "R" Then
intTotalRep += 1
Else
intTotalInd += 1
End If
Loop
inFile.Close()
txtDemo.Text = intTotalDem.ToString
txtRep.Text = intTotalRep.ToString
txtInde.Text = intTotalInd.ToString
Else
MessageBox.Show("pao.txt file not found.", "Politcal Awareness Organization", MessageBoxButtons.OK, MessageBoxIcon.Information)
End If
End Sub
End Class
8. During July and August of each year, the Political Awareness Organization (PAO) sends a questionnaire to the voters in its district. The questionnaire asks each voter for his or her political party (Democratic, Republican, or Independent) and age. From the returned questionnaires, the organization's secretary tabulates the number of Democrats, Republicans, and Independents in the district. The secretary wants an application that she can use to save each respondent's information (political party and age) to a sequential access file. The application should also calculate and display the number of voters in each political party. Create a Visual Basic Windows application. Use the following names for the solution and project, respectively: PAO Solution and PAO Project. Save the application in the ClearlyVB2012|Chap22 folder. Change the name of the form file on your disk to frmMain.vb. If necessary change the form's name to frmMain. Create the interface shown in Figure 22-15. The Party text box should accept only the Backspace key and the letters D, d, R, r I, or i. The Age text box should accept only numbers and the Backspace key. Code the Click event procedures for the Write to File and Display Totals buttons. Save the solution and then start and test the application. Close the Code Editor window and then close the solution.Explanation / Answer
ANSWER:
To display the count there are many appraches below the simple one for this requirement.
# using the while loop read all the content of the file and store it in varaible
# now you have all the content of the file in the string variable
# now convert all the string in lowecase since use can enter D,d,R,r,I,i
# by converting to lowercase we don't have to care in which case user enter the value
# now using for loop extract each character from the string and check if they are the required one
# if the character is r,d,i then increment their respective variable
# now display variable data in the textfeild
BELOW IS THE CODE for btnDisplay_Click function
read comments for more detail
Private Sub btnDisplay_Click(sender As Object, e As EventArgs) Handles btnDisplay.Click
' reads names from a sequential access file
' and displays them in the interface
' declare variables
Dim inFile As IO.StreamReader
' clear previous names from the Contestants box
txtParty.Text = String.Empty
' determine whether the file exists
If IO.File.Exists("f:\party.txt") = True Then
inFile = IO.File.OpenText("f:\party.txt")
'######### ADDED THE BELOW CODE
'Create String to store the file content
Dim fileData As String
'Read all the lines in file and append it to the fileData
'Read while there is content in file
While (inFile.Peek >= 0)
fileData += inFile.ReadLine()
End While
'convert all the text to lowercase
'By this we save time by not comparing the uppper case
'eg : if data stored is D98 it will get converted to d98
'Since there is no difference between D and d we can convert to lowercase [as per application requirement]
' ToLower() convert the string in lowecase
fileData = fileData.ToLower()
'Variables to store the count of D,R,I
'Initalise them with 0 to remove any garbage value
Dim dcount = 0, rcount = 0, icount = 0
'Run the loop to get the each char in the "fileData" and compare if it is D,I,R
'Loop need to be run till the length of the "fileData" (means the number of char)
'we just check each character if it is i,r,d then increment their respective variable
For x = 1 To fileData.Length Step 1
'get the char at position
' if filedata contain "D54 r65" then value at 1 position is D
' GetChar return the character at specific position
Dim charx = GetChar(fileData, x)
Console.WriteLine(charx)
'check if i then increment
If charx = "i" Then
icount = icount + 1
End If
'check if d then increment
If charx = "d" Then
dcount = dcount + 1
End If
'check if r then increment
If charx = "r" Then
rcount = rcount + 1
End If
Next
'^^ end the loop
'now set the value in the textFeild
txtd.Text = dcount 'set the value of democratic textfeild
txti.Text = icount 'set the value of Republician textFeid
txtr.Text = rcount 'set the value of independent textFeild
'Now close the FileStream
inFile.Close()
'###############################3
Else
MessageBox.Show("Can't find the file", "party.txt",
MessageBoxButtons.OK,
MessageBoxIcon.Information)
End If
End Sub
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