01 Loops

Which one of these is a valid loop statement in Go?

1. while
2. forever
3. until
4. for CORRECT

4: Correct. There is only one loop statement in Go.

What does this code print?

for i := 3; i > 0; i-- {
    fmt.Println(i)
}

1. 3 2 1 CORRECT
2. 1 2 3
3. 0 1 2
4. 2 1 0

What does this code print?

for i := 3; i > 0; {
    i--
    fmt.Println(i)
}

1. 3 2 1
2. 1 2 3
3. 0 1 2
4. 2 1 0 CORRECT

What does this code print?

for i := 3; ; {
    if i <= 0 {
        break
    }

    i--
    fmt.Println(i)
}

1. 3 2 1
2. 1 2 3
3. 0 1 2
4. 2 1 0 CORRECT

What does this code print?

for i := 2; i <= 9; i++ {
    if i % 3 != 0 {
        continue
    }

    fmt.Println(i)
}

1. 3 6 9 CORRECT
2. 9 6 3
3. 2 3 6 9
4. 2 3 4 5 6 7 8 9

How can you simplify this code?

for ; true ; {
    // ...
}

1. goCopy

   for true {
   }
   

2. goCopy

   for true; {
   }
   

3. goCopy

   for {
   }
   

   CORRECT
4. goCopy

   for ; true {
   }
   

What does this code print?

Let's say that you run the program like this:

go run main.go go is awesome

for i, v := range os.Args[1:] {
    fmt.Println(i+1, v)
}

1. Copy

   1 go
   2 is
   3 awesome
   

   CORRECT
2. Copy

   go
   is
   awesome
   

3. Copy

   0 go
   1 is
   2 awesome
   

4. Copy

   1
   2
   3
   

What does this code print?

Let's say that you run the program like this:

go run main.go go is awesome

for i := range os.Args[1:] {
    fmt.Println(i+1)
}

1. Copy

   1 go
   2 is
   3 awesome
   

2. Copy

   go
   is
   awesome
   

3. Copy

   0 go
   1 is
   2 awesome
   

4. Copy

   1
   2
   3
   

   CORRECT

What does this code print?

Let's say that you run the program like this:

go run main.go go is awesome

for _, v := range os.Args[1:] {
    fmt.Println(v)
}

1. Copy

   1 go
   2 is
   3 awesome
   

2. Copy

   go
   is
   awesome
   

   CORRECT
3. Copy

   0 go
   1 is
   2 awesome
   

4. Copy

   1
   2
   3
   

What does this code print?

Let's say that you run the program like this:

go run main.go go is awesome

var i int

for range os.Args {
    i++
}

fmt.Println(i)

1. go is awesome
2. 1 2 3
3. 2
4. 4 CORRECT

4: As you can see, you can also use a for range statement for counting things.