Explain the use of Go's embedding for code reuse?

In Go, embedding is a mechanism for code reuse that allows a struct type to include fields and methods of another struct type, without explicitly declaring them. This is often used to build more complex types out of simpler types, and to reuse existing code without duplicating it.

To embed a struct type in another struct type, we simply declare a field of the embedded type, without giving it a field name. This is called an anonymous field. For example, suppose we have a struct type **Person** that has a **Name** field and a **Greet** method:

type Person struct {
    Name string
}

func (p *Person) Greet() {
    fmt.Printf("Hello, my name is %s\n", p.Name)
}

We can then define another struct type **Employee** that embeds **Person** and adds a **Salary** field:

type Employee struct {
    Person  // anonymous field of type Person
    Salary float64
}

Here, **Employee** embeds **Person** as an anonymous field. This means that **Employee** inherits the **Name** field and **Greet** method from **Person**, without having to declare them explicitly.

We can then create an instance of **Employee** and use its inherited **Name** field and **Greet** method:

e := Employee{Person: Person{Name: "Alice"}, Salary: 50000.0}
e.Greet()  // prints "Hello, my name is Alice"

We can also define a **NewEmployee** function that takes a name and a salary and returns a new **Employee** with the **Person** field initialized:

func NewEmployee(name string, salary float64) *Employee {
    return &Employee{Person: Person{Name: name}, Salary: salary}
}

Here, we use the **Person** field to initialize the **Name** field of the embedded **Person** struct.

In summary, embedding is a mechanism for code reuse in Go that allows a struct type to include fields and methods of another struct type, without explicitly declaring them. This is often used to build more complex types out of simpler types, and to reuse existing code without duplicating it. To embed a struct type, we declare an anonymous field of the embedded type, and then use it to access the embedded fields and methods.