отредактирована 3 глава

part_3/3.7/golang/factory/go.mod

@@ -0,0 +1,3 @@
+module golang/factory
+
+go 1.24

part_3/3.7/golang/factory/main.go

@@ -0,0 +1,85 @@
+package main
+
+import (
+	"fmt"
+	"golang/factory/shape"
+)
+
+func printShapeName(name shape.IShapeName) {
+	fmt.Printf("IShapeName: %v\n", name.GetName())
+}
+
+func getIShapeFromRectangle(rectangle *shape.Rectangle) shape.IShape {
+	return rectangle // неявное приведение
+	// return shape.IShape(rectangle) // явное приведение
+}
+
+func main() {
+	rectangle := shape.NewRectangle(10, 6, shape.Point{X: 6, Y: -8}, "Gold")
+
+	ishape := shape.IShape(rectangle) // приведение Rectangle к интерфейсу
+	// приведение интерфейса IShape к интерфейсу IShapeArea
+	iShapeArea := shape.IShapeArea(ishape)
+	fmt.Printf("IShapeArea: %+v\n", iShapeArea.GetArea())
+
+	// явное обратное приведение интерфейса IShapePerimeter к интерфейсу IShape невозможно
+	// ishape = shape.IShape(iShapePerimeter) //error:
+	// cannot convert iShapePerimeter (variable of type shape.IShapePerimeter) to shape.IShape
+	// (shape.IShapePerimeter does not implement shape.IShape (missing method GetArea))
+
+	// правильное приведение интерфейса IShapeArea к интерфейсу IShape
+	ishape = iShapeArea.(*shape.Rectangle)
+	// аналогично
+	// newIshape := shape.IShape(iShapeArea.(*shape.Rectangle))
+	fmt.Printf("IShape center: %+v\n", ishape.GetCenter())
+
+	// правильное приведение интерфейса IShapeArea к структуре Rectangle
+	rectangle = iShapeArea.(*shape.Rectangle)
+	fmt.Printf("%s: %+v\n", rectangle.GetName(), *rectangle)
+}
+
+// func main() {
+// 	rectangle1 := shape.NewRectangle(10, 6, shape.Point{X: 6, Y: -8}, "Gold")
+// 	triangle1 := shape.NewTriangle(6, 10, 8, shape.Point{X: -85, Y: 15}, "Green")
+// 	rectangle2 := shape.NewRectangle(3, 5, shape.Point{X: 46, Y: -48}, "Yellow")
+// 	triangle2 := shape.NewTriangle(4, 8, 6, shape.Point{X: 61, Y: 98}, "Orange")
+
+// 	// объявляем и инициализируем срез интерфейсного типа
+// 	ishapeSlice := []shape.IShape{
+// 		rectangle1,
+// 		triangle1,
+// 		triangle2,
+// 		rectangle2,
+// 	}
+
+// 	for _, it := range ishapeSlice {
+// 		fmt.Printf("Shape center coordinate: %+v\n", it.GetCenter())
+// 		newCenter := shape.Point{
+// 			X: it.GetCenter().X + 33,
+// 			Y: it.GetCenter().Y - 20,
+// 		}
+// 		it.MoveCenter(newCenter)
+// 		fmt.Printf("Shape new center coordinate: %+v\n", it.GetCenter())
+// 		fmt.Println()
+// 	}
+// }
+
+// func main() {
+// 	rectangle := shape.NewRectangle(10, 6, shape.Point{X: 6, Y: -8}, "Gold")
+// 	triangle := shape.NewTriangle(6, 10, 8, shape.Point{X: -85, Y: 15}, "Green")
+// 	printShapeName(rectangle)                   // неявное приведение
+// 	//printShapeName(shape.IShapeName(rectangle)) // явное приведение
+// 	printShapeName(triangle)
+// 	ishape := getIShapeFromRectangle(rectangle)
+// 	fmt.Printf("Shape center: %v\n", ishape.GetCenter())
+// 	fmt.Printf("Shape perimeter: %v\n", ishape.GetPerimeter())
+// }
+
+// func main() {
+// 	rectangle := shape.NewRectangle(10, 6, shape.Point{X: 6, Y: -8}, "Gold")
+// 	triangle := shape.NewTriangle(6, 10, 8, shape.Point{X: -85, Y: 15}, "Green")
+// 	iShapeName := shape.IShapeName(triangle) // приведение Triangle к интерфейсу
+// 	fmt.Printf("IShapeName: %v\n", iShapeName.GetName())
+// 	iShapeName = shape.IShapeName(rectangle) // приведение Rectangle к интерфейсу
+// 	fmt.Printf("IShapeName: %v\n", iShapeName.GetName())
+// }

part_3/3.7/golang/factory/shape/ishape.go

@@ -0,0 +1,20 @@
+package shape
+
+type IShape interface {
+	GetArea() float64
+	GetPerimeter() uint
+	MoveCenter(point Point)
+	GetCenter() Point
+}
+
+type IShapeArea interface {
+	GetArea() float64
+}
+
+type IShapePerimeter interface {
+	GetPerimeter() uint
+}
+
+type IShapeName interface {
+	GetName() string
+}

part_3/3.7/golang/factory/shape/rectangle.go

@@ -0,0 +1,47 @@
+package shape
+
+type Rectangle struct {
+	shape  // композиция
+	width  uint
+	length uint
+}
+
+func (r *Rectangle) GetWidth() uint {
+	return r.width
+}
+
+func (r *Rectangle) GetLength() uint {
+	return r.length
+}
+
+func (r *Rectangle) SetWidth(width uint) {
+	r.width = width
+}
+
+func (r *Rectangle) SetLength(length uint) {
+	r.length = length
+}
+
+func (r *Rectangle) GetPerimeter() uint {
+	return (r.length + r.width) * 2
+}
+
+func (r *Rectangle) GetArea() float64 {
+	return float64(r.length * r.width)
+}
+
+func (r *Rectangle) GetName() string {
+	return "Super-puper " + r.shape.GetName()
+}
+
+func NewRectangle(width, length uint, center Point, color string) *Rectangle {
+	return &Rectangle{
+		shape: shape{
+			name:   "Rectangle",
+			color:  color,
+			center: center,
+		},
+		width:  width,
+		length: length,
+	}
+}

part_3/3.7/golang/factory/shape/shape.go

@@ -0,0 +1,32 @@
+package shape
+
+type Point struct {
+	X int
+	Y int
+}
+
+type shape struct {
+	name   string
+	center Point
+	color  string
+}
+
+func (s *shape) SetColor(color string) {
+	s.color = color
+}
+
+func (s *shape) GetColor() string {
+	return s.color
+}
+
+func (s *shape) GetName() string {
+	return s.name
+}
+
+func (s *shape) MoveCenter(point Point) {
+	s.center = point
+}
+
+func (s *shape) GetCenter() Point {
+	return s.center
+}

part_3/3.7/golang/factory/shape/triangle.go

@@ -0,0 +1,64 @@
+package shape
+
+import "math"
+
+type Triangle struct {
+	shape
+	abLength uint
+	acLength uint
+	bcLength uint
+}
+
+func (t *Triangle) GetABLength() uint {
+	return t.abLength
+}
+
+func (t *Triangle) GetACLength() uint {
+	return t.acLength
+}
+
+func (t *Triangle) GetBCLength() uint {
+	return t.bcLength
+}
+
+func (t *Triangle) SetABLength(ab uint) {
+	t.abLength = ab
+}
+
+func (t *Triangle) SetACLength(ac uint) {
+	t.abLength = ac
+}
+
+func (t *Triangle) SetBCLength(bc uint) {
+	t.abLength = bc
+}
+
+func (t *Triangle) GetPerimeter() uint {
+	return t.abLength + t.acLength + t.bcLength
+}
+
+func (t *Triangle) GetArea() float64 {
+	// расчет площади треугольника
+	// высота рассчитывается по формуле разностороннего треугольника
+	// через длины всех сторон
+	p := float64(t.GetPerimeter() / 2) // полупериметр
+	numerator := p * (p - float64(t.abLength)) *
+		(p - float64(t.acLength)) *
+		(p - float64(t.acLength))
+	numerator = 2 * math.Sqrt(numerator)
+	height := numerator / 2
+	return float64(t.acLength) / 2 * height
+}
+
+func NewTriangle(ab, ac, bc uint, center Point, color string) *Triangle {
+	return &Triangle{
+		shape: shape{
+			name:   "Triangle",
+			color:  color,
+			center: center,
+		},
+		abLength: ab,
+		bcLength: bc,
+		acLength: ac,
+	}
+}