golang 2. 变量

package main

/*
	四种变量的声明方式
*/

import (
	"fmt"
)

//声明全局变量 方法一、方法二、方法三是可以的
var gA int = 100
var gB = 200

//用方法四来声明全局变量
// := 只能够用在 函数体内来声明
//gC := 200

func main() {
	//方法一：声明一个变量 默认的值是0
	var a int
	fmt.Println("a = ", a)
	fmt.Printf("type of a = %T
", a)

	//方法二：声明一个变量，初始化一个值
	var b int = 100
	fmt.Println("b = ", b)
	fmt.Printf("type of b = %T
", b)

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

	//方法三：在初始化的时候，可以省去数据类型，通过值自动匹配当前的变量的数据类型
	var c = 100
	fmt.Println("c = ", c)
	fmt.Printf("type of c = %T
", c)

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

	//方法四：(常用的方法) 省去var关键字，直接自动匹配
	e := 100
	fmt.Println("e = ", e)
	fmt.Printf("type of e = %T
", e)

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

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

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

	// 声明多个变量
	var xx, yy int = 100, 200
	fmt.Println("xx = ", xx, ", yy = ", yy)
	var kk, ll = 100, "Aceld"
	fmt.Println("kk = ", kk, ", ll = ", ll)

	//多行的多变量声明
	var (
		vv int  = 100
		jj bool = true
	)
	fmt.Println("vv = ", vv, ", jj = ", jj)
}