main.go 源码
// Copyright © 2018 Inanc Gumus
// Learn Go Programming Course
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
//
// For more tutorials : https://learngoprogramming.com
// In-person training : https://www.linkedin.com/in/inancgumus/
// Follow me on twitter: https://twitter.com/inancgumus
package main
import (
"fmt"
"strconv"
)
func main() {
local := 10
show(local)
incrWrong(local)
fmt.Printf("local → %d\n", local)
// incr(local)
local = incr(local)
show(local)
local = incrBy(local, 5)
show(local)
_, err := incrByStr(local, "TWO")
if err != nil {
fmt.Printf("err → %s\n", err)
}
local, _ = incrByStr(local, "2")
show(local)
// CHAINING
// can't save the number back into main's local
show(incrBy(local, 2))
show(local)
// can't pass the results of the multiple-value returning func
// show(incrByStr(local, "3"))
// can call showErr directly because it accepts the same types
// of parameters as with incrByStr's result values.
// local = sanitize(incrByStr(local, "NOPE"))
// show(local)
local = sanitize(incrByStr(local, "2"))
show(local)
local = limit(incrBy(local, 5), 2000)
show(local)
}
func show(n int) {
// can't access main's local
// fmt.Printf("show : n = %d\n", local)
fmt.Printf("show → n = %d\n", n)
}
// wrong: incr can't access to main's `local`
func incrWrong(n int) {
// n := local
n++
// can't return (there are no result values)
// return n
}
func incr(n int) int {
n++
return n
}
func incrBy(n, factor int) int {
return n * factor
}
func incrByStr(n int, factor string) (int, error) {
m, err := strconv.Atoi(factor)
n = incrBy(n, m)
return n, err
}
func sanitize(n int, err error) int {
if err != nil {
return 0
}
return n
}
func limit(n, lim int) (m int) {
// var m int
m = n
if m >= lim {
m = lim
}
// return m
return
}
你可能感兴趣的文章
go main
go main
go main
go main
go main
go Header
go main
go main
go main
go main