[Go语言] go语言中iota和左移右移的使用说明

package iota
import "fmt"
func Test()  {
const(
c1 = iota  //c1=0
c2 = iota  //c2=1
c3 = iota  //c3=2
)
fmt.Println("c1 = ",c1," c2 = ",c2," c3 = ",c3,"\n")
const(
a = 1 << iota //a = 1
b = 1 << iota //b = 2
c = 1 << iota //c = 4
)
fmt.Println("a = ",a," b = ",b," c = ",c,"\n")
const(
v1 = iota //v1 = 0
v2    //v2 = 1
v3    //v3 = 2
)
fmt.Println("v1 = ",v1," v2 = ",v2," v3 = ",v3,"\n")
const(
x = 1 <<iota //x = 1
y  //y = 2
z       //z = 4
)
fmt.Println("x = ",x," y = ",y," z = ",z)
}

// 1.iota常量自动生成器,每隔一行,自动累加1
// 2.iota给常量赋值用
const (
a = iota //0
b = iota //1
c = iota //2
)
fmt.Printf("a = %d, b = %d, c = %d\n", a, b, c)
 
 
// 3.iota遇到const,重置为0
const d = iota
fmt.Printf("d = %d\n", d)
 
 
// 4 可以只写一个iota
const (
a1 = iota //0
b1    //1
c1    //2
)
fmt.Printf("a1 = %d, b1 = %d, c1 = %d\n", a1, b1, c1)
 
 
// 5 如果是同一行,值都一样
const (
i      = iota
j1, j2, j3 = iota, iota, iota
k      = iota
)
 
fmt.Printf("i = %d, j1 = %d, j2 = %d, j3 = %d, k = %d\n", i, j1, j2, j3, k)