go中常量及iota的使用

package main
//常量的使用
import (
   "fmt"
   "unsafe"
)

const (
   A="ABCD"
   Sorce=98
   C = unsafe.Sizeof(A)  //常量表达式中，函数必须是内置函数，否则编译不过
)

func main(){

   //在每一个const关键字出现时，被重置为0，然后再下一个const出现之前，每出现一次iota，其所代表的数字会自动增加1
   const (
      Unknown = 0
      Female = 1
      Male = 2
      a1 = iota  //3
      b1 = iota  //4
      c1 = iota  //5
   )
   const LENGTH int = 10
   const WIDTH int = 5
   const a, b, c = 1, false, "str" //多重赋值
   println(a1,b1,c1)

   const (
      a3 = iota   //0
      b3          //1
      c3          //2
      d3 = "ha"   //独立值，iota += 1
      e3          //"ha"   iota += 1
      f3 = 100    //iota +=1
      g3          //100  iota +=1
      h3 = iota   //7,恢复计数
      i3          //8
   )
   fmt.Println(a3,b3,c3,d3,e3,f3,g3,h3,i3)
}