126 lines
3.2 KiB
Plaintext
126 lines
3.2 KiB
Plaintext
' version 17-09-2015
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' compile with: fbc -s console
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#Define screen_width 1024
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#Define screen_height 256
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ScreenRes screen_width, screen_height, 8
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Width screen_width\8, screen_height\16
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Function f1(x As Double) As Double
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Return x^3
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End Function
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Function f2(x As Double) As Double
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Return 1/x
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End Function
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Function f3(x As Double) As Double
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Return x
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End Function
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Function leftrect(a As Double, b As Double, n As Double, _
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ByVal f As Function (ByVal As Double) As Double) As Double
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Dim As Double sum, x = a, h = (b - a) / n
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For i As UInteger = 1 To n
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sum = sum + h * f(x)
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x = x + h
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Next
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leftrect = sum
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End Function
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Function rightrect(a As Double, b As Double, n As Double, _
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ByVal f As Function (ByVal As Double) As Double) As Double
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Dim As Double sum, x = a, h = (b - a) / n
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For i As UInteger = 1 To n
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x = x + h
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sum = sum + h * f(x)
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Next
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rightrect = sum
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End Function
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Function midrect(a As Double, b As Double, n As Double, _
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ByVal f As Function (ByVal As Double) As Double) As Double
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Dim As Double sum, h = (b - a) / n, x = a + h / 2
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For i As UInteger = 1 To n
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sum = sum + h * f(x)
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x = x + h
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Next
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midrect = sum
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End Function
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Function trap(a As Double, b As Double, n As Double, _
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ByVal f As Function (ByVal As Double) As Double) As Double
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Dim As Double x = a, h = (b - a) / n
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Dim As Double sum = h * (f(a) + f(b)) / 2
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For i As UInteger = 1 To n -1
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x = x + h
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sum = sum + h * f(x)
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Next
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trap = sum
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End Function
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Function simpson(a As Double, b As Double, n As Double, _
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ByVal f As Function (ByVal As Double) As Double) As Double
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Dim As UInteger i
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Dim As Double sum1, sum2
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Dim As Double h = (b - a) / n
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For i = 0 To n -1
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sum1 = sum1 + f(a + h * i + h / 2)
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Next i
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For i = 1 To n -1
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sum2 = sum2 + f(a + h * i)
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Next i
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simpson = h / 6 * (f(a) + f(b) + 4 * sum1 + 2 * sum2)
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End Function
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' ------=< main >=------
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Dim As Double y
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Dim As String frmt = " ##.##########"
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Print
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Print "function range steps leftrect midrect " + _
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"rightrect trap simpson "
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Print "f(x) = x^3 0 - 1 100";
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Print Using frmt; leftrect(0, 1, 100, @f1); midrect(0, 1, 100, @f1); _
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rightrect(0, 1, 100, @f1); trap(0, 1, 100, @f1); simpson(0, 1, 100, @f1)
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Print "f(x) = 1/x 1 - 100 1000";
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Print Using frmt; leftrect(1, 100, 1000, @f2); midrect(1, 100, 1000, @f2); _
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rightrect(1, 100, 1000, @f2); trap(1, 100, 1000, @f2); _
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simpson(1, 100, 1000, @f2)
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frmt = " #########.###"
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Print "f(x) = x 0 - 5000 5000000";
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Print Using frmt; leftrect(0, 5000, 5000000, @f3); midrect(0, 5000, 5000000, @f3); _
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rightrect(0, 5000, 5000000, @f3); trap(0, 5000, 5000000, @f3); _
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simpson(0, 5000, 5000000, @f3)
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Print "f(x) = x 0 - 6000 6000000";
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Print Using frmt; leftrect(0, 6000, 6000000, @f3); midrect(0, 6000, 6000000, @f3); _
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rightrect(0, 6000, 6000000, @f3); trap(0, 6000, 6000000, @f3); _
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simpson(0, 6000, 6000000, @f3)
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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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