package main

import "fmt"

type Address struct {
	City   string
	Street string
}

type Person struct {
	Name    string
	Age     int
	Address Address
}

type Employee struct {
	Person
	EmployeeID int
	Department string
}

type Employee2 struct {
	____
	Salary float64
}

type Reader interface {
	Read() string
}

type Writer interface {
	Write(s string)
}

type File struct {
	Name    string
	Content string
}

func (f File) Read() string {
	return f.___
}

func (f *File) Write(s string) {
	f.Content = ____
}

type ReadWriter interface {
	____
	____
}

func exercise1() string {
	fmt.Println("=== 练习1：结构体嵌入 ===")

	emp := Employee{
		Person: Person{
			Name: "张三",
			Age:  30,
		},
		EmployeeID: 1001,
		Department: "技术部",
	}

	fmt.Printf("员工姓名: %s, 年龄: %d\n", ____, emp.___)

	return ____
}

func exercise2() string {
	fmt.Println("=== 练习2：多层嵌入 ===")

	address := Address{City: "北京", Street: "长安街"}

	emp2 := Employee2{
		Person: Person{
			Name:    "李四",
			Address: ____,
		},
		Salary: 10000.0,
	}

	fmt.Printf("员工: %s, 城市: %s\n", emp2.___, emp2.___.City)

	return ____
}

func exercise3() string {
	fmt.Println("=== 练习3：接口实现 ===")

	file := File{Name: "test.txt", Content: "初始内容"}

	// 使用Read方法
	content := file.____()
	fmt.Printf("读取内容: %s\n", content)

	// 使用Write方法
	file.____("新内容")
	fmt.Printf("写入后内容: %s\n", file.___)

	return ___
}

func exercise4() string {
	fmt.Println("=== 练习4：接口组合 ===")

	file := &File{Name: "data.txt", "原始数据"}

	var rw _____

	rw.Write("修改后的数据")
	result := rw.Read()

	fmt.Printf("读写结果: %s\n", result)

	return ____
}

func exercise5() string {
	fmt.Println("=== 练习5：类型断言 ===")

	var data interface{} = "Hello, Go!"

	// 尝试断言为string
	str, ok := data.____
	if ok {
		fmt.Printf("类型断言成功: %s\n", ____)
	}

	// 尝试断言为int
	_, ok = data.____
	if !ok {
		fmt.Println("类型断言失败: 不是int类型")
	}

	return "类型断言演示完成"
}

func exercise6() string {
	fmt.Println("=== 练习6：类型选择 ===")

	values := []interface{}{10, "hello", 3.14, true}

	for _, v := range ____ {
		switch v.(type) {
		case int:
			fmt.Printf("整数: %d\n", ____)
		case string:
			fmt.Printf("字符串: %s\n", ____)
		case float64:
			fmt.Printf("浮点数: %.2f\n", ____)
		case bool:
			fmt.Printf("布尔值: %t\n", ____)
		default:
			fmt.Println("未知类型")
		}
	}

	return "类型选择演示完成"
}

func main() {
	fmt.Println("=== 组合与类型断言 练习 ===\n")

	result1 := exercise1()
	fmt.Printf("练习1结果: %s\n", result1)

	result2 := exercise2()
	fmt.Printf("练习2结果: %s\n", result2)

	result3 := exercise3()
	fmt.Printf("练习3结果: %s\n", result3)

	result4 := exercise4()
	fmt.Printf("练习4结果: %s\n", result4)

	result5 := exercise5()
	fmt.Printf("练习5结果: %s\n", result5)

	result6 := exercise6()
	fmt.Printf("练习6结果: %s\n", result6)
}