package main

/*
四种声明变量的方式
*/

import (
	"fmt"
)

var gA int = 100
var gB = 200

func main() {
	// 方法一：声明一个亦是 默认的值是0
	var a int
	fmt.Println("a = ", a)
	fmt.Printf("type of a is %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\ntype of bb is %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\ntype of cc is %T\n", cc, cc)

	// 方法四：(常用的方法）省略var关键字，直接自动匹配，:=只能用在函数体内，不能用于声明全局变量
	e := 100
	fmt.Println("e = ", e)
	fmt.Printf("type of e is %T\n", e)

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

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

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

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