mirror of
https://github.com/gopl-zh/gopl-zh.github.com.git
synced 2024-11-05 14:03:45 +00:00
41 lines
680 B
Go
41 lines
680 B
Go
|
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
|
||
|
|
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
|
||
|
|
|
||
|
|
// See page 73.
|
||
|
|
|
||
|
|
// Comma prints its argument numbers with a comma at each power of 1000.
|
||
|
|
//
|
||
|
|
// Example:
|
||
|
|
// $ go build gopl.io/ch3/comma
|
||
|
|
// $ ./comma 1 12 123 1234 1234567890
|
||
|
|
// 1
|
||
|
|
// 12
|
||
|
|
// 123
|
||
|
|
// 1,234
|
||
|
|
// 1,234,567,890
|
||
|
|
//
|
||
|
|
package main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"os"
|
||
|
|
)
|
||
|
|
|
||
|
|
func main() {
|
||
|
|
for i := 1; i < len(os.Args); i++ {
|
||
|
|
fmt.Printf(" %s\n", comma(os.Args[i]))
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
//!+
|
||
|
|
// comma inserts commas in a non-negative decimal integer string.
|
||
|
|
func comma(s string) string {
|
||
|
|
n := len(s)
|
||
|
|
if n <= 3 {
|
||
|
|
return s
|
||
|
|
}
|
||
|
|
return comma(s[:n-3]) + "," + s[n-3:]
|
||
|
|
}
|
||
|
|
|
||
|
|
//!-
|