46 lines
926 B
Go
46 lines
926 B
Go
// 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"
|
|
"os"
|
|
"strconv"
|
|
)
|
|
|
|
func main() {
|
|
if a := os.Args; len(a) != 2 {
|
|
|
|
// only a is available here
|
|
fmt.Println("Give me a number.")
|
|
|
|
// no need to return on error
|
|
// return
|
|
|
|
} else if n, err := strconv.Atoi(a[1]); err != nil {
|
|
|
|
// a, n and err are available here
|
|
fmt.Printf("Cannot convert %q.\n", a[1])
|
|
|
|
// no need to return on error
|
|
// return
|
|
|
|
} else {
|
|
// all of the variables (names)
|
|
// are available here
|
|
fmt.Printf("%s * 2 is %d\n", a[1], n*2)
|
|
}
|
|
|
|
// a, n and err are not available here
|
|
// they belong to the if statement
|
|
|
|
// TRY:
|
|
// fmt.Println(a, n, err)
|
|
}
|