mirror of
https://github.com/gopl-zh/gopl-zh.github.com.git
synced 2024-12-26 23:06:20 +00:00
47 lines
713 B
Go
47 lines
713 B
Go
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
|
|
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
|
|
|
|
// See page 244.
|
|
|
|
// Countdown implements the countdown for a rocket launch.
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"os"
|
|
"time"
|
|
)
|
|
|
|
//!+
|
|
|
|
func main() {
|
|
// ...create abort channel...
|
|
|
|
//!-
|
|
|
|
//!+abort
|
|
abort := make(chan struct{})
|
|
go func() {
|
|
os.Stdin.Read(make([]byte, 1)) // read a single byte
|
|
abort <- struct{}{}
|
|
}()
|
|
//!-abort
|
|
|
|
//!+
|
|
fmt.Println("Commencing countdown. Press return to abort.")
|
|
select {
|
|
case <-time.After(10 * time.Second):
|
|
// Do nothing.
|
|
case <-abort:
|
|
fmt.Println("Launch aborted!")
|
|
return
|
|
}
|
|
launch()
|
|
}
|
|
|
|
//!-
|
|
|
|
func launch() {
|
|
fmt.Println("Lift off!")
|
|
}
|