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31 lines
698 B
31 lines
698 B
2 years ago
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Exercise 5.21: Implement register machines for
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the following procedures. Assume that the list-structure memory operations are
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available as machine primitives.
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Recursive count-leaves:
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(define (count-leaves tree)
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(cond ((null? tree) 0)
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((not (pair? tree)) 1)
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(else
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(+ (count-leaves (car tree))
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(count-leaves (cdr tree))))))
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Recursive count-leaves with explicit counter:
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(define (count-leaves tree)
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(define (count-iter tree n)
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(cond ((null? tree) n)
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((not (pair? tree)) (+ n 1))
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(else
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(count-iter
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(cdr tree)
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(count-iter (car tree)
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n)))))
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(count-iter tree 0))
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