fix: coding style and file format for all example.

eBook/examples/chapter_11/interfaces_poly.go

@@ -1,45 +1,43 @@
-// interfaces_poly.go
-package main
-
-import "fmt"
-
-type Shaper interface {
-	Area() float32
-}
-
-type Square struct {
-	side float32
-}
-
-func (sq *Square) Area() float32 {
-	return sq.side * sq.side
-}
-
-type Rectangle struct {
-   length, width float32
-}
-
-func (r Rectangle) Area() float32 {
-   return r.length * r.width
-}
-
-func main() {
-   r := Rectangle{5, 3} // Area() of Rectangle needs a value
-   q := &Square{5}      // Area() of Square needs a pointer
-   shapes := []Shaper{r, q}
-   fmt.Println("Looping through shapes for area ...")
-   for n, _ := range shapes {
-       fmt.Println("Shape details: ", shapes[n])
-       fmt.Println("Area of this shape is: ", shapes[n].Area())
-   }
-}
-/* Output:
-Looping through shapes for area ...
-Shape details:  {5 3}
-Area of this shape is:  15
-Shape details:  &{5}
-Area of this shape is:  25
-*/
-
-
-
+// interfaces_poly.go
+package main
+
+import "fmt"
+
+type Shaper interface {
+	Area() float32
+}
+
+type Square struct {
+	side float32
+}
+
+func (sq *Square) Area() float32 {
+	return sq.side * sq.side
+}
+
+type Rectangle struct {
+	length, width float32
+}
+
+func (r Rectangle) Area() float32 {
+	return r.length * r.width
+}
+
+func main() {
+	r := Rectangle{5, 3} // Area() of Rectangle needs a value
+	q := &Square{5}      // Area() of Square needs a pointer
+	shapes := []Shaper{r, q}
+	fmt.Println("Looping through shapes for area ...")
+	for n := range shapes {
+		fmt.Println("Shape details: ", shapes[n])
+		fmt.Println("Area of this shape is: ", shapes[n].Area())
+	}
+}
+
+/* Output:
+Looping through shapes for area ...
+Shape details:  {5 3}
+Area of this shape is:  15
+Shape details:  &{5}
+Area of this shape is:  25
+*/