go學習之常量與枚舉

const特徵

• const filename = "abc.txt"
• const數值可作爲各種類型使用
• const a, b = 3, 4
• var c int = int(math.Sqrt(a*a + b*b)

iota表示枚舉類型自增

• 直接用iota賦初值，默認爲0
• iota可參與運算

package main

import (
	"fmt"
	"math"
	"math/cmplx"
)

func enums() {
	/* author:      Na2S2O3
	 * date:        2019-08-28
	 * function:    枚舉
	 */
	// iota表示自增，默認從0開始
	const (
		cpp = iota
		java
		python
		golang
	)
	fmt.Println(cpp, java, python, golang)
	const (
		b = 1 << (10 * iota)
		kb
		mb
		gb
		tb
		pb
	)
	fmt.Println(b, kb, mb, gb, tb, pb)
}

func consts() {
	/*  author:      Na2S2O3
	 *  date:        2019-08-28
	 *  function:    常量
	 */
	const (
		filename = "abc.txt"
		a, b            = 3, 4
	)
	var c int
	c = int(math.Sqrt(a*a + b*b))
	fmt.Println(filename, c)
}

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

)