「A Tour of Go」でGo言語を学ぶ(~#28) ref: http://qiita.com/items/ddaa13be965e15185dad

file1.txt

4

file3.txt

{1 2} &{1 2} {1 0} {0 0}

struct.go

package main

import "fmt"

type Vertex struct {
    X int
    Y int
}

func main() {
    v := Vertex{1, 2}
    v.X = 4
    fmt.Println(v.X)
}

struct2.go

package main

import "fmt"

type Vertex struct {
    X, Y int
}

var (
    p = Vertex{1, 2}  // has type Vertex
    q = &Vertex{1, 2} // has type *Vertex
    r = Vertex{X: 1}  // Y:0 is implicit
    s = Vertex{}      // X:0 and Y:0
)

func main() {
    fmt.Println(p, q, r, s)
}