area calculated

interfaces/demo1.go

@@ -0,0 +1,38 @@
+package interfaces
+
+import (
+	"fmt"
+	"math"
+)
+
+type shape interface{
+	area() float64
+}
+
+type rectangle struct{
+	rectangle_width, rectangle_height float64
+}
+
+type circle struct{
+	radius float64
+}
+
+func (r rectangle) area() float64{
+	return r.rectangle_height * r.rectangle_width
+}
+
+func (c circle) area() float64 {
+	return math.Pi * c.radius * c.radius
+}
+
+func school(s shape)  {
+	fmt.Println("Area : ", s.area())
+}
+
+func Demo1()  {
+	r:= rectangle{
+		rectangle_width: 10, rectangle_height: 6,
+	}
+
+	school(r)
+}

main.go

@@ -8,6 +8,7 @@ import (
 	"golesson/examplerange"
 	"golesson/functions"
 	"golesson/goroutines"
+	"golesson/interfaces"
 	"golesson/loops"
 	"golesson/maps"
 	"golesson/pointers"
@@ -75,4 +76,6 @@ func main() {
 	multiply := EvenNumberTotal * OddNumberTotal
 
 	fmt.Println("Multiply Result : ", multiply)
+
+	interfaces.Demo1()
 }