38 lines
838 B
Go
38 lines
838 B
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"
|
|
"os"
|
|
"strconv"
|
|
)
|
|
|
|
func main() {
|
|
// UNCOMMENT THIS TO SEE IT IN ACTION:
|
|
// var n int
|
|
|
|
if a := os.Args; len(a) != 2 {
|
|
fmt.Println("Give me a number.")
|
|
} else if n, err := strconv.Atoi(a[1]); err != nil {
|
|
// else if here shadows the main func's n
|
|
// variable and it declares it own
|
|
// with the same name: n
|
|
|
|
fmt.Printf("Cannot convert %q.\n", a[1])
|
|
} else {
|
|
fmt.Printf("%s * 2 is %d\n", a[1], n*2)
|
|
}
|
|
|
|
// n here belongs to the main func
|
|
// not to the if statement above
|
|
|
|
// UNCOMMENT ALSO LINES BELOW TO SEE IT IN ACTION:
|
|
// fmt.Printf("n is %d. 👻 👻 👻 - you've been shadowed ;-)", n)
|
|
}
|