1 package main
2
3 import (
4 "flag"
5 "os"
6 "strconv"
7 )
8
9 func main() {
10 var sub bool
11 flag.BoolVar(&sub, "sub", false, "whether to subtract arguments instead of add")
12
13 flag.Parse()
14
15 if flag.NArg() < 2 {
16 os.Stdout.WriteString("bad arguments\n")
17 os.Exit(1)
18 }
19
20 a, err := strconv.Atoi(flag.Arg(0))
21 if err != nil {
22 os.Stdout.WriteString("bad arguments\n")
23 os.Exit(1)
24 }
25
26 b, err := strconv.Atoi(flag.Arg(1))
27 if err != nil {
28 os.Stdout.WriteString("bad arguments\n")
29 os.Exit(1)
30 }
31
32 var res int
33 if sub {
34 res = a - b
35 } else {
36 res = a + b
37 }
38
39 os.Stdout.WriteString("result: " + strconv.Itoa(res) + "\n")
40 }
41
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