58 lines
705 B
Go
58 lines
705 B
Go
package main
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// interfaces example
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import (
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"fmt"
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"math"
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)
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type Shape interface {
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area() float64
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perim() float64
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}
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type Circle struct {
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r float64
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}
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func (c Circle) area() float64 {
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return c.r * c.r * math.Pi
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}
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func (c Circle) perim() float64 {
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return 2 * math.Pi * c.r
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}
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type Rect struct {
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a float64
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b float64
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}
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func (r Rect) area() float64 {
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return r.a * r.b
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}
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func (r Rect) perim() float64 {
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return (r.a + r.b) * 2.0
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}
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func main() {
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c := Circle{
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r: 5.0,
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}
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r := Rect{
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a: 2.0,
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b: 3.0,
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}
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showShape("Circle", c)
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showShape("Rect", r)
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}
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func showShape(name string, s Shape) {
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fmt.Printf("%v area %.2f\n", name, s.area())
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fmt.Printf("%v area %.2f\n\n", name, s.perim())
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}
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