iota

 1 //iota作用会自动递增,引用自己定义的表达式。
 2 
 3 
 4 //定义所有星期,从0到6
 5 package main
 6 
 7 import "fmt"
 8 
 9 const (
10     Sunday = iota    //重点
11     Monday
12     Tuesday
13     Wednesday
14     Thursday
15     Friday
16     Saturday
17 )
18 
19 func main() {
20 
21     //从第二个开始,自动引用排头兵的表达式,但iota逐一递增.
22     fmt.Println(Sunday, Monday, Tuesday) //0 1 2 
23 
24 }

 

 1 ////定义所有星期,从1到7
 2 package main
 3 
 4 import "fmt"
 5 
 6 const (
 7     Monday = iota +1 //0 +1 = 1   //重点
 8     Tuesday
 9     Wednesday
10     Thursday
11     Friday
12     Saturday
13     Sunday
14 )
15 
16 func main() {
17 
18     //从第二个开始,自动引用排头兵的表达式,但iota逐一递增.
19     fmt.Println(Monday, Tuesday) //1 2
20 
21 }

 

 1 //定义5大常任理事国编号100-500
 2 
 3 package main
 4 
 5 import "fmt"
 6 
 7 const (
 8     USA = (iota + 1) * 100  //重点
 9     China
10     Russia
11     Britain
12     France
13 )
14 
15 func main() {
16 
17     fmt.Println(USA, China, Russia, Britain, France) //100 200 300 400 500
18 
19 }