35 lines
1016 B
Racket
35 lines
1016 B
Racket
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#! /usr/bin/racket
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#lang racket/base
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(define (accumulate-iter combiner null-value term a next b)
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(define (iter a result)
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(if (> a b)
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result
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(iter (next a) (combiner (term a) result))))
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(iter a null-value))
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(define (product-iter term a next b)
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(accumulate-iter * 1 term a next b))
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(define (sum-iter term a next b)
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(accumulate-iter + 0 term a next b))
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(sum-iter (lambda (x) x) 1 (lambda (x) (+ x 1)) 4)
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(product-iter (lambda (x) x) 1 (lambda (x) (+ x 1)) 4)
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define (accumulate-recur combiner null-value term a next b)
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(if (> a b)
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null-value
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(combiner (term a)
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(accumulate-recur combiner null-value term (next a) next b))))
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(define (product-recur term a next b)
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(accumulate-recur * 1 term a next b))
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(define (sum-recur term a next b)
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(accumulate-recur + 0 term a next b))
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(sum-recur (lambda (x) x) 1 (lambda (x) (+ x 1)) 4)
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(product-recur (lambda (x) x) 1 (lambda (x) (+ x 1)) 4)
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