package main

import (
	"fmt"
)

type Vertex struct {
	X int
	Y int
}

func main() {

	fmt.Println("A struct is a collection of fields")
	fmt.Println(Vertex{1, 2})

	fmt.Println("struct fields are accessed by using a dot")
	v := Vertex{6, 8}
	fmt.Printf("%T, %v\n", v, v)
	fmt.Printf("%T, %v\n", v.X, v.X)
	fmt.Printf("%T, %v\n", v.Y, v.Y)

	fmt.Printf("\n\n")

	fmt.Println("Struct fields can be accessed through a struct pointer")
	v2 := Vertex{6, 8}
	p := &v2
	// var p *Vertex = &v2 // ALSO VALID

	(*p).X = 10
	fmt.Printf("%T, %v, %p\n", p, p, p)
	fmt.Printf("%T, %v\n", *p, *p)

	fmt.Println("Go also allows to use struct pointers without * symbol while accesing elements:")
	p.X = 15 // VALID
	fmt.Println(*p)

	fmt.Printf("\n\n")

	fmt.Println("You can also use struct literals for assigning struct elements")
	var (
		v3 = Vertex{10, 20}
		v4 = Vertex{X: 1} // Y:0
		v5 = Vertex{}     // X:0, Y:0
		v6 = Vertex{Y: 15, X: 75}
		p2 = &Vertex{1, 2}
	)

	fmt.Printf("%T, %v\n", v3, v3)
	fmt.Printf("%T, %v\n", v4, v4)
	fmt.Printf("%T, %v\n", v5, v5)
	fmt.Printf("%T, %v\n", v6, v6)
	fmt.Printf("%T, %v\n", p2, p2)
	fmt.Printf("%T, %v\n", *p2, *p2)

}