29 lines
541 B
Racket
29 lines
541 B
Racket
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(define (divide a b)
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(define (iter a b product)
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(cond ((= a 0) product)
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((< a 0) (- product 1))
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(else (iter (- a b) b (+ product 1)))))
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(iter a b 0))
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; divide
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(define (halve a)
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(divide a 2))
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(define (double a)
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(+ a a))
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(define (multiply a b)
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(define (iter a b product)
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(cond ((= a 1) (+ product b))
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((even? a) (iter (halve a) (double b) product))
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(else (iter (halve a) (double b) (+ product b)))))
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(iter a b 0))
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; multiply
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(multiply 132 555)
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(multiply 32 2)
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(multiply 33 1)
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