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39 lines
616 B
Go
39 lines
616 B
Go
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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// See page 218.
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// Spinner displays an animation while computing the 45th Fibonacci number.
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package main
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import (
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"fmt"
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"time"
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)
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//!+
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func main() {
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go spinner(100 * time.Millisecond)
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const n = 45
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fibN := fib(n) // slow
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fmt.Printf("\rFibonacci(%d) = %d\n", n, fibN)
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}
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func spinner(delay time.Duration) {
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for {
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for _, r := range `-\|/` {
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fmt.Printf("\r%c", r)
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time.Sleep(delay)
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}
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}
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}
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func fib(x int) int {
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if x < 2 {
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return x
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}
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return fib(x-1) + fib(x-2)
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}
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//!-
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