Imports System
Imports System.IO
Imports System.Reflection
Imports System.Text.RegularExpressions

Public Class FreqAnalysis


    Public Function CharCount(ByVal OrigString As String, _
    ByVal Chars As String, Optional ByVal CaseSensitive As Boolean = False) _
      As Long

        '**********************************************
        'PURPOSE: Returns Number of occurrences of a character or
        'or a character sequencence within a string

        'PARAMETERS:
        'OrigString: String to Search in
        'Chars: Character(s) to search for
        'CaseSensitive (Optional): Do a case sensitive search
        'Defaults to false

        'RETURNS:
        'Number of Occurrences of Chars in OrigString

        'EXAMPLES:
        'Debug.Print CharCount("FreeVBCode.com", "E") -- returns 3
        'Debug.Print CharCount("FreeVBCode.com", "E", True) -- returns 0
        'Debug.Print CharCount("FreeVBCode.com", "co") -- returns 2
        ''**********************************************

        Dim lLen As Long
        Dim lCharLen As Long
        Dim lAns As Long
        Dim sInput As String
        Dim sChar As String
        Dim lCtr As Long
        Dim lEndOfLoop As Long
        Dim bytCompareType As Byte

        sInput = OrigString
        If sInput = "" Then Exit Function
        lLen = Len(sInput)
        lCharLen = Len(Chars)
        lEndOfLoop = (lLen - lCharLen) + 1
        bytCompareType = IIf(CaseSensitive, vbBinaryCompare, _
           vbTextCompare)

        For lCtr = 1 To lEndOfLoop
            sChar = Mid(sInput, lCtr, lCharLen)
            If StrComp(sChar, Chars, bytCompareType) = 0 Then _
                lAns = lAns + 1
        Next

        CharCount = lAns

    End Function

    Private Sub anB_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles anB.Click
        Dim analysise As String
        analysise = AnTxt.Text.ToUpper

        'Single letter analysis

        'Count
        Dim numA As Integer
        numA = CharCount(analysise, "A")
        Dim numB As Integer
        numB = CharCount(analysise, "B")
        Dim numC As Integer
        numC = CharCount(analysise, "C")
        Dim numD As Integer
        numD = CharCount(analysise, "D")
        Dim numE As Integer
        numE = CharCount(analysise, "E")
        Dim numF As Integer
        numF = CharCount(analysise, "F")
        Dim numG As Integer
        numG = CharCount(analysise, "G")
        Dim numH As Integer
        numH = CharCount(analysise, "H")
        Dim numI As Integer
        numI = CharCount(analysise, "I")
        Dim numJ As Integer
        numJ = CharCount(analysise, "J")
        Dim numK As Integer
        numK = CharCount(analysise, "K")
        Dim numL As Integer
        numL = CharCount(analysise, "L")
        Dim numM As Integer
        numM = CharCount(analysise, "M")
        Dim numN As Integer
        numN = CharCount(analysise, "N")
        Dim numO As Integer
        numO = CharCount(analysise, "O")
        Dim numP As Integer
        numP = CharCount(analysise, "P")
        Dim numQ As Integer
        numQ = CharCount(analysise, "Q")
        Dim numR As Integer
        numR = CharCount(analysise, "R")
        Dim numS As Integer
        numS = CharCount(analysise, "S")
        Dim numT As Integer
        numT = CharCount(analysise, "T")
        Dim numU As Integer
        numU = CharCount(analysise, "U")
        Dim numV As Integer
        numV = CharCount(analysise, "V")
        Dim numW As Integer
        numW = CharCount(analysise, "W")
        Dim numX As Integer
        numX = CharCount(analysise, "X")
        Dim numY As Integer
        numY = CharCount(analysise, "Y")
        Dim numZ As Integer
        numZ = CharCount(analysise, "Z")

        'Display Normal English Percentages

        NumEngA.Text = "8.4966"
        NumEngB.Text = "2.0720"
        NumEngC.Text = "4.5388"
        NumEngD.Text = "3.3844"
        NumEngE.Text = "11.1607"
        NumEngF.Text = "1.8121"
        NumEngG.Text = "2.4705"
        NumEngH.Text = "3.0034"
        NumEngI.Text = "7.5448"
        NumEngJ.Text = "0.1965"
        NumEngK.Text = "1.1016"
        NumEngL.Text = "5.4893"
        NumEngM.Text = "3.0129"
        NumEngN.Text = "6.6544"
        NumEngO.Text = "7.1635"
        NumEngP.Text = "3.1671"
        NumEngQ.Text = "0.1962"
        NumEngR.Text = "7.5809"
        NumEngS.Text = "5.7351"
        NumEngT.Text = "6.9509"
        NumEngU.Text = "3.6308"
        NumEngV.Text = "1.0074"
        NumEngW.Text = "1.2899"
        NumEngX.Text = "0.2902"
        NumEngY.Text = "1.7779"
        NumEngZ.Text = "0.2722"
        'e.t.c.

        'Display Ciphertext Numbers

        NumCiphA.Text = numA
        NumCiphB.Text = numB
        NumCiphC.Text = numC
        NumCiphD.Text = numD
        NumCiphE.Text = numE
        NumCiphF.Text = numF
        NumCiphG.Text = numG
        NumCiphH.Text = numH
        NumCiphI.Text = numI
        NumCiphJ.Text = numJ
        NumCiphK.Text = numK
        NumCiphL.Text = numL
        NumCiphM.Text = numM
        NumCiphN.Text = numN
        NumCiphO.Text = numO
        NumCiphP.Text = numP
        NumCiphQ.Text = numQ
        NumCiphR.Text = numR
        NumCiphS.Text = numS
        NumCiphT.Text = numT
        NumCIphU.Text = numU
        NumCiphV.Text = numV
        NumCiphW.Text = numW
        NumCiphX.Text = numX
        NumCiphY.Text = numY
        NumCiphZ.Text = numZ

        'Work Out Percentages

        Dim l As Integer = AnTxt.Text.Length
        Dim perA
        perA = numA / l * 100
        Dim perB
        perB = numB / l * 100
        Dim perC
        perC = numC / l * 100
        Dim perD
        perD = numD / l * 100
        Dim perE
        perE = numE / l * 100
        Dim perF
        perF = numF / l * 100
        Dim perG
        perG = numG / l * 100
        Dim perH
        perH = numH / l * 100
        Dim perI
        perI = numI / l * 100
        Dim perJ
        perJ = numJ / l * 100
        Dim perK
        perK = numK / l * 100
        Dim perL
        perL = numL / l * 100
        Dim perM
        perM = numM / l * 100
        Dim perN
        perN = numN / l * 100
        Dim perO
        perO = numO / l * 100
        Dim perP
        perP = numP / l * 100
        Dim perQ
        perQ = numQ / l * 100
        Dim perR
        perR = numR / l * 100
        Dim perS
        perS = numS / l * 100
        Dim perT
        perT = numT / l * 100
        Dim perU
        perU = numU / l * 100
        Dim perV
        perV = numV / l * 100
        Dim perW
        perW = numW / l * 100
        Dim perX
        perX = numX / l * 100
        Dim perY
        perY = numY / l * 100
        Dim perZ
        perZ = numZ / l * 100

        'Display Ciphertext Percentages

        PerCiphA.Text = perA
        PerCiphB.Text = perB
        PerCiphC.Text = perC
        PerCiphD.Text = perD
        PerCiphE.Text = perE
        PerCiphF.Text = perF
        PerCiphG.Text = perG
        PerCiphH.Text = perH
        PerCiphI.Text = perI
        PerCiphJ.Text = perJ
        PerCiphK.Text = perK
        PerCiphL.Text = perL
        PerCiphM.Text = perM
        PerCiphN.Text = perN
        PerCiphO.Text = perO
        PerCiphP.Text = perP
        PerCiphQ.Text = perQ
        PerCiphR.Text = perR
        PerCiphS.Text = perS
        PerCiphT.Text = perT
        PerCiphU.Text = perU
        PerCiphV.Text = perV
        PerCiphW.Text = perW
        PerCiphX.Text = perX
        PerCiphY.Text = perY
        PerCiphZ.Text = perZ


        'Pair letter analysis


        'Repeated letter analysis
    End Sub

    Private Sub Paste_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Paste.Click
        AnTxt.Text = Clipboard.GetText
    End Sub

    Private Sub Copy_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Copy.Click

    End Sub
End Class

#include <iostream>
#include <string>
#include <algorithm>

size_t CharCount(const char* line, char Ch, bool CaseSensitive = false)
{
     size_t count = 0;
     size_t i;
     std::string dup;
     dup = line;
     if(CaseSensitive == true)
     {
           std::transform(dup.begin(),dup.end(),dup.begin(), toupper);
     }
    // now count the letters
    for(i = 0; i < dup.size(); ++i)
    {
          if( dup[i] ==  Ch)
             ++count;
     }
     return count;

}

void anB_Click()
{
    size_t counts[26] = {0};
    int percentages[26] = {0};
    size_t len;
    char* string = "This is the string to be used";

    for(int i = 0; i < 26; i++)
         counts[i] = CharCount(string, i+'A');
    len = strlen(string);
    for(int i = 0; i < 26; i++)
        percentages[i] = (int) (((float)counts[i] / (float)len) * 100.0F);   

}