27 lines
762 B
Scheme
27 lines
762 B
Scheme
(import (scheme base) ;; library imports in R7RS style
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(scheme write)
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(srfi 1 lists))
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(define (factorial n)
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(fold * 1 (iota n 1)))
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(define (left-factorial n)
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(fold + 0 (map factorial (iota n))))
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(define (show i r) ; to pretty print the results
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(display "!") (display i) (display " ") (display r) (newline))
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;; show left factorials for zero through ten (inclusive)
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(for-each
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(lambda (i) (show i (left-factorial i)))
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(iota 11))
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;; show left factorials for 20 through 110 (inclusive) by tens
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(for-each
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(lambda (i) (show i (left-factorial i)))
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(iota 10 20 10))
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;; number of digits in 1000 through 10000 by thousands:
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(for-each
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(lambda (i) (show i (string-length (number->string (left-factorial i)))))
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(iota 10 1000 1000))
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