Structs, Methods, and Interfaces

Structs

This lesson explains the main concept clearly with beginner-friendly examples and background so you can learn why the code works.

Structs group related fields.

type Person struct {
    Name string
    Age  int
}

p := Person{Name: "Bob", Age: 30}

Methods (receiver functions)

func (p Person) Greet() string {
    return "Hello, " + p.Name
}

func (p *Person) HaveBirthday() {
    p.Age++ // pointer receiver mutates the struct
}

Interfaces (behavioral contracts)

type Greeter interface {
    Greet() string
}

func Say(g Greeter) {
    fmt.Println(g.Greet())
}

Say(p) // Person implements Greeter

Interfaces are satisfied implicitly – no implements keyword.