62 lines
1.5 KiB
Plaintext
62 lines
1.5 KiB
Plaintext
' version 25-06-2015
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' compile with: fbc -s console
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Function calc_entropy(source As String, base_ As Integer) As Double
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Dim As Integer i, sourcelen = Len(source), totalchar(255)
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Dim As Double prop, entropy
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For i = 0 To sourcelen -1
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totalchar(source[i]) += 1
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Next
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For i = 0 To 255
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If totalchar(i) = 0 Then Continue For
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prop = totalchar(i) / sourcelen
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entropy = entropy - (prop * Log (prop) / Log(base_))
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Next
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Return entropy
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End Function
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' ------=< MAIN >=------
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Dim As String fw1 = "1" , fw2 = "0", fw3
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Dim As Integer i, n
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Print" N Length Entropy Word"
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n = 1
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Print Using " ###";n; : Print Using " ###########"; Len(fw1);
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Print Using " ##.############### "; calc_entropy(fw1,2);
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Print fw1
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n = 2
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Print Using " ###";n ;: Print Using " ###########"; Len(fw2);
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Print Using " ##.############### "; calc_entropy(fw2,2);
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Print fw2
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For n = 1 To 35
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fw1 = "1" : fw2 = "0" ' construct string
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For i = 1 To n
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fw3 = fw2 + fw1
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Swap fw1, fw2 ' swap pointers of fw1 and fw2
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Swap fw2, fw3 ' swap pointers of fw2 and fw3
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Next
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fw1 = "" : fw3 = "" ' free up memory
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Print Using " ### ########### ##.############### "; n +2; Len(fw2);_
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calc_entropy(fw2, 2);
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If Len(fw2) < 55 Then Print fw2 Else Print
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Next
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Print
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' empty keyboard buffer
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While InKey <> "" : Wend
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Print : Print "hit any key to end program"
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Sleep
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End
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