变量的声明

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\n", 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\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\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关键字，直接自动匹配
   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)

   // 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)
}