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21 lines
504 B
21 lines
504 B
2 years ago
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Exercise 1.9: Each of the following two
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procedures defines a method for adding two positive integers in terms of the
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procedures inc, which increments its argument by 1, and dec,
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which decrements its argument by 1.
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(define (+ a b)
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(if (= a 0)
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b
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(inc (+ (dec a) b))))
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(define (+ a b)
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(if (= a 0)
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b
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(+ (dec a) (inc b))))
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Using the substitution model, illustrate the process generated by each
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procedure in evaluating (+ 4 5). Are these processes iterative or
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recursive?
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