Go常量与枚举类型

package main

import (
    "math"
    "fmt"
)

//常量与枚举
//const数值可作为各种类型使用

func consts()  {
    const fliename  = "abc.txt"  //常量名字不一定要全部大写
    const a, b  = 3, 4  //不定义类型又可以int 又可以float，可以不用强制类型转换
    var c int
    c = int ( math.Sqrt( a * a + b * b))
    fmt.Println( fliename, c)  //abc.txt 5
}

func enums()  {
    const(
        cpp = 0
        java = 1
        python = 2
        golang = 3
    )
    fmt.Println( cpp, java, python, golang)  //0 1 2 3
}

func enums1()  {
    const(
        cpp = iota  //自增值
        _
        python
        golang
        javascript
    )

    const(
        b = 1 << ( 10 * iota)
        kb
        mb
        gb
        tb
        pb
    )
    fmt.Println( cpp,  python, golang, javascript)  //0 2 3 4
    fmt.Println(b, kb, mb, gb, tb, pb)  //1 1024 1048576 1073741824 1099511627776 1125899906842624
}

func main() {
    consts()
    enums()
    enums1()
}