go by example part 2

5-go-by-example/19-methods.go

@@ -0,0 +1,32 @@
+// methods defined on struct types
+
+package main
+
+import "fmt"
+
+type rect struct {
+	width, height int
+}
+
+// area method has a receiver type of *rect
+func (r *rect) area() int {
+	return r.width * r.height
+}
+
+// Methods can be defined for either pointer or value receiver types
+func (r rect) perim() int {
+	return 2*r.width + 2*r.height
+}
+
+func main() {
+	r := rect{width: 10, height: 5}
+
+	// call 2 methods defined for the struct
+	fmt.Println("area: ", r.area())
+	fmt.Println("perim:", r.perim())
+
+	// Go automatically handles conversion between values and pointers for method calls
+	rp := &r
+	fmt.Println("area: ", rp.area())
+	fmt.Println("perim:", rp.perim())
+}