package main

/*
	四種變數的宣告方式
*/

import (
	"fmt"
)

//宣告全域性變數 方法一、方法二、方法三是可以的
var gA int = 100
var gB = 200

//用方法四來宣告全域性變數
// := 只能夠用在 函式體內來宣告
//gC := 200

func main() {
	//方法一：宣告一個變數 預設的值是0
	var a int
	fmt.Println("a = ", a)
	fmt.Printf("type of a = %T\n", a)

	//方法二：宣告一個變數，初始化一個值
	var b int = 100
	fmt.Println("b = ", b)
	fmt.Printf("type of b = %T\n", b)

	var bb string = "abcd"
	fmt.Printf("bb = %s, type of bb = %T\n", bb, bb)

	//方法三：在初始化的時候，可以省去資料型別，通過值自動匹配當前的變數的資料型別
	var c = 100
	fmt.Println("c = ", c)
	fmt.Printf("type of c = %T\n", c)

	var cc = "abcd"
	fmt.Printf("cc = %s, type of cc = %T\n", cc, cc)

	//方法四：(常用的方法) 省去var關鍵字，直接自動匹配
	e := 100
	fmt.Println("e = ", e)
	fmt.Printf("type of e = %T\n", e)

	f := "abcd"
	fmt.Println("f = ", f)
	fmt.Printf("type of f = %T\n", f)

	g := 3.14
	fmt.Println("g = ", g)
	fmt.Printf("type of g = %T\n", g)

	// =====
	fmt.Println("gA = ", gA, ", gB = ", gB)
	//fmt.Println("gC = ", gC)

	// 宣告多個變數
	var xx, yy int = 100, 200
	fmt.Println("xx = ", xx, ", yy = ", yy)
	var kk, ll = 100, "Aceld"
	fmt.Println("kk = ", kk, ", ll = ", ll)

	//多行的多變數宣告
	var (
		vv int  = 100
		jj bool = true
	)
	fmt.Println("vv = ", vv, ", jj = ", jj)
}