48 lines
768 B
Text
48 lines
768 B
Text
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class
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APPLICATION
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create
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make
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feature
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make
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-- Test of the mutually recursive functions Female and Male.
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do
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across
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0 |..| 19 as c
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loop
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io.put_string (Female (c.item).out + " ")
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end
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io.new_line
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across
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0 |..| 19 as c
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loop
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io.put_string (Male (c.item).out + " ")
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end
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end
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Female (n: INTEGER): INTEGER
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-- Female sequence of the Hofstadter Female and Male sequences.
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require
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n_not_negative: n >= 0
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do
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Result := 1
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if n /= 0 then
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Result := n - Male (Female (n - 1))
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end
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end
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Male (n: INTEGER): INTEGER
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-- Male sequence of the Hofstadter Female and Male sequences.
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require
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n_not_negative: n >= 0
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do
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Result := 0
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if n /= 0 then
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Result := n - Female (Male (n - 1))
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end
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end
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end
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