16 lines
408 B
Racket
16 lines
408 B
Racket
#lang racket
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(printf "Input a string: ")
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(define s (read-line))
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(printf "You entered: ~a\n" s)
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(printf "Input a number: ")
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(define m (or (string->number (read-line))
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(error "I said a number!")))
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(printf "You entered: ~a\n" m)
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;; alternatively, use the generic `read'
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(printf "Input a number: ")
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(define n (read))
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(unless (number? n) (error "I said a number!"))
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(printf "You entered: ~a\n" n)
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