Go语言学习5-常量

// Constants
package main

import "math"
import "fmt"

//const declares a constant value.
const s string = "constant"

func main() {
    fmt.Println(s)
    //A const statement can appear anywhere a var statement can.
    const n = 500000000
    //Constant expressions perform arithmetic with arbitrary precision.
    const d = 3e20 / n
    fmt.Println(d)
    //A numeric constant has no type until it’s given one, such as by an explicit cast.
    fmt.Println(int64(d))
    //A number can be given a type by using it in a context that requires one,
    //such as a variable assignment or function call.
    //For example, here math.Sin expects a float64.
    fmt.Println(math.Sin(n))
}

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