43 lines
834 B
Go
43 lines
834 B
Go
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// 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 156.
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// Package geometry defines simple types for plane geometry.
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//!+point
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package geometry
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import "math"
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type Point struct{ X, Y float64 }
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// traditional function
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func Distance(p, q Point) float64 {
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return math.Hypot(q.X-p.X, q.Y-p.Y)
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}
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// same thing, but as a method of the Point type
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func (p Point) Distance(q Point) float64 {
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return math.Hypot(q.X-p.X, q.Y-p.Y)
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}
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//!-point
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//!+path
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// A Path is a journey connecting the points with straight lines.
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type Path []Point
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// Distance returns the distance traveled along the path.
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func (path Path) Distance() float64 {
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sum := 0.0
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for i := range path {
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if i > 0 {
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sum += path[i-1].Distance(path[i])
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}
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}
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return sum
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}
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//!-path
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