103 lines
1.7 KiB
Go
103 lines
1.7 KiB
Go
|
// For more tutorials: https://blog.learngoprogramming.com
|
||
|
|
//
|
||
|
|
// Copyright © 2018 Inanc Gumus
|
||
|
|
// Learn Go Programming Course
|
||
|
|
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
|
||
|
|
//
|
||
|
|
|
||
|
|
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
|
||
|
|
}
|