Extract a shape interface

1 files changed, 30 insertions, 0 deletions

diff --git a/shapes.go b/shapes.go
new file mode 100644
index 0000000..7853871
--- /dev/null
+++ b/shapes.go
@@ -0,0 +1,30 @@
+package main
+
+import (
+	"math"
+)
+
+func Perimeter(rectangle Rectangle) float64 {
+	return 2 * (rectangle.Width + rectangle.Height)
+}
+
+type Shape interface {
+	Area() float64
+}
+
+type Rectangle struct {
+	Width  float64
+	Height float64
+}
+
+func (r Rectangle) Area() float64 {
+	return r.Width * r.Height
+}
+
+type Circle struct {
+	Radius float64
+}
+
+func (c Circle) Area() float64 {
+	return math.Pi * c.Radius * c.Radius
+}