19/2 14.17

Author: r-vb

basics/interfaces.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+// shape interface
+type shape interface {
+	area() float64
+	circumf() float64
+}
+
+type square struct {
+	length float64
+}
+type circle struct {
+	radius float64
+}
+
+// square methods
+func (s square) area() float64 {
+	return s.length * s.length
+}
+func (s square) circumf() float64 {	// same as perimeter
+	return s.length * 4
+}
+
+// circle methods
+func (c circle) area() float64 {
+	return math.Pi * c.radius * c.radius
+}
+func (c circle) circumf() float64 { // same as perimeter
+	return 2 * math.Pi * c.radius
+}
+
+func printShapeInfo(s shape) {
+	fmt.Printf("area of %T is: %0.2f \n", s, s.area())
+	fmt.Printf("circumference of %T is: %0.2f \n", s, s.circumf())
+}
+
+func main() {
+	shapes := []shape{
+		square{length: 15.2},
+		circle{radius: 7.5},
+		circle{radius: 12.3},
+		square{length: 4.9},
+	}
+
+	for _, v := range shapes {
+		printShapeInfo(v)
+		fmt.Println("-----")
+	}
+}