if,for等可以有初始化表达式的，其作用域还要高于其后的花括号一层

package main

func main() {

	x:=1
	println(x)
	
	for x:=3;;{
		print(x," ")
		break
	}
	println(x)
	
	if x:=5; true {
		print(x," ")
	}
	println(x)
	
	for {
		x:=7
		print(x," ")
		break
	}
	println(x)
	
	if true {
		x:=9
		print(x," ")
	}
	println(x)

	if x:=2; true {
		print(x," ")
		x:="abc"
		print(x," ")
	}
	println(x)
	
	for x:=4;; {
		print(x," ")
		x:="def"
		print(x," ")
		break
	}
	println(x)
}

// 1
// 3 1
// 5 1
// 7 1
// 9 1
// 2 abc 1
// 4 def 1