54 lines
No EOL
1.1 KiB
Go
54 lines
No EOL
1.1 KiB
Go
package main
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import (
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"fmt"
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"math"
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)
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// here is a basic interface for geometric shapes
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type geometry interface {
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area() float64
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perim() float64
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}
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//for our example well implement this interface on rect and circle types
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type rect struct {
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width,height float64
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}
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type circle struct {
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radius float64
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}
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// to implement an interface in Go,
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//we just need to implement all the methods in the interface
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//here we do it for rectangles
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func (r rect) area() float64 {
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return r.width * r.height
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}
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func (r rect) perim() float64 {
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return 2*r.width + 2*r.height
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}
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//here we do it for circles
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func (c circle) area() float64 {
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return math.Pi * c.radius * c.radius
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}
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func (c circle) perim() float64 {
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return 2*math.Pi*c.radius
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}
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//if a variable has an interface type,
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// then we can call methods that are in the named interface
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//here's a generic measure function taking advantage of this
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//to work on any geometry
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func measure(g geometry) {
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fmt.Println(g)
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fmt.Println(g.area())
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fmt.Println(g.perim())
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}
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func main(){
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r := rect{width: 3,height: 4}
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c := circle{radius:5}
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measure(r)
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measure(c)
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} |