38 lines
679 B
Go
38 lines
679 B
Go
package main
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import "fmt"
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import "math"
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type Circle struct {
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x, y, r float64
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}
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func (c *Circle) area() float64 {
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return math.Pi * c.r * c.r
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}
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type Rectangle struct {
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x1, y1, x2, y2 float64
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}
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func distance(x1, y1, x2, y2 float64) float64 {
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a := x2 - x1
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b := y2 - y1
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return math.Sqrt(a*a + b*b)
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}
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func (r *Rectangle) area() float64 {
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l := distance(r.x1, r.y1, r.x1, r.y2)
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w := distance(r.x1, r.y1, r.x2, r.y1)
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return l * w
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}
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func main() {
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circle := Circle{x: 0, y: 3, r: 5}
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fmt.Println(circle.area())
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rectangle := Rectangle{x1: 3, x2: 10, y1: 5, y2: 7}
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fmt.Println(rectangle.area())
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}
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// todo: pointer vs value receivers
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