package main //必须

import (
	"calc"
	"fmt"
)

//2、再执行这个init打印
func init() {
	fmt.Println("this is main init")
}

func main() {
	a := calc.Add(10, 20)
	fmt.Println("a = ", a)

	fmt.Println("r = ", calc.Minus(10, 5))
}

package calc

import "fmt"

//1、先执行这个init打印
func init() {
	fmt.Println("this is calc init")
}

//func add(a, b int) int {
func Add(a, b int) int {
	return a + b
}

func Minus(a, b int) int {
	return a - b
}　

this is calc init
this is main init
a =  30
r =  5