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Go by Example - Constants

翻译自 https://gobyexample.com/

Go by Example

Go is an open source programming language designed for building simple, fast, and reliable software.

Go by Example is a hands-on introduction to Go using annotated example programs. Check out the first example or browse the full list below.

Go by Example: Constants

golang支持字符型、字符串型、布尔型和数值型的常量。

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package main
import "fmt"
import "math"
// const关键字生命常量
const s string = "constant"
func main() {
fmt.Println(s)
// const常量可以在任何变量可以声明的地方声明,并且支持科学计数法等算术运算
const n = 500000000
const d = 3e20 / n
fmt.Println(d)
// 数值型常量默认没有特定的类型,可以显式声明类型,也默认会根据上下文自动确定自身类型
// 例如下面的语句`math.Sin`函数需要float64类型的参数,n就默认确定为float64类型
fmt.Println(int64(d))
fmt.Println(math.Sin(n))
}
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$: go run constant.go
constant
6e+11
600000000000
-0.28470407323754404

原文链接:Go by Example: Constants