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Questions - cons

Every solution that I've seen for SICP Exercise 3.16 appears to cheat by creating more than three pairs. Where is my misunderstanding?

SICP Exercise 3.16 gives the reader a broken procedure for counting the numbers of pairs in a list structure: (define (count-pairs x) (if (not (pair? x)) 0 (+ (count-pairs (car x)) ...
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J. Mini

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sicp

cons

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Latest Answer

Write it as (define x (cons 'foo '())) (define y (cons x x)) (define str2 (cons y '())) How many conses? Three conses! But when we count them, x is counted twice, so (cons x x) ==> (+ 1 1 1)...
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Will Ness

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