lesson8: 函数，闭包和方法（可以再补充一点：函数高级用法）

[Chao2020x]

package main

import "fmt"
import "math"

// define function getSquareRoot1
func getSquareRoot1(x float64) float64 {
return math.Sqrt(x)
}

// deffine a function variable
var getSquareRoot2 = func(x float64) float64 {
return math.Sqrt(x)
}

// deffine a function variable ========================补充
var getSquareRoot3 = math.Sqrt