listing28.go

// Code listing 28: https://play.golang.org/p/OMCP5KFC10

// Go's _structs_ are typed collections of fields.
// They're useful for grouping data together to form
// records.

package main

import "fmt"

// This `person` struct type has `name` and `age` fields.
type person struct {
    name string
    age  int
}

func main() {

    // This syntax creates a new struct.
    fmt.Println(person{"Bob", 20})

    // You can name the fields when initializing a struct.
    fmt.Println(person{name: "Alice", age: 30})

    // Omitted fields will be zero-valued.
    fmt.Println(person{name: "Fred"})

    // An `&` prefix yields a pointer to the struct.
    fmt.Println(&person{name: "Ann", age: 40})

    // Access struct fields with a dot.
    s := person{name: "Sean", age: 50}
    fmt.Println(s.name)

    // You can also use dots with struct pointers - the
    // pointers are automatically dereferenced.
    sp := &s
    fmt.Println(sp.age)

    // Structs are mutable.
    sp.age = 51
    fmt.Println(sp.age)
}