Channel closing behavior in Go - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to close the channel.

Go

ch := make(chan int)
// Close the channel
[1](ch)

Drag options to blanks, or click blank then click option'

Aclose

BcloseChan

CchanClose

Dshutdown

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-existent function like closeChan or chanClose.

Trying to assign nil to the channel instead of closing it.

The close function is used to close a channel in Go.

2fill in blank

medium

Complete the code to receive from a closed channel without blocking.

Go

ch := make(chan int)
go func() {
    close(ch)
}()

value, [1] := <-ch

Drag options to blanks, or click blank then click option'

Aclosed

Bdone

Cok

Dreceived

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name other than 'ok' which is conventional.

Not using the two-value receive syntax.

The second value when receiving from a channel indicates if the channel is open (true) or closed (false).

3fill in blank

hard

Fix the error in the code that tries to send on a closed channel.

Go

ch := make(chan int)
go func() {
    close(ch)
}()

// This will cause a panic
[1] ch <- 5

Drag options to blanks, or click blank then click option'

A// do not send

Bclose(ch)

Cselect

Dch <- 5

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to close the channel again.

Using select without proper case to avoid sending.

Sending on a closed channel causes a panic. To fix it, do not send after closing.

4fill in blank

hard

Fill both blanks to create a map comprehension that stores lengths of words longer than 3 characters.

Go

words := []string{"go", "code", "chat", "bot"}
lengths := map[string]int{}
for _, word := range words {
    if len(word) [1] 3 {
        lengths[[2]] = len(word)
    }
}

Drag options to blanks, or click blank then click option'

A>

Bword

C<

Dlen

Attempts:

3 left

💡 Hint

Common Mistakes

Using less than instead of greater than.

Using len instead of word as the map key.

The condition checks if the word length is greater than 3, and the map key is the word itself.

5fill in blank

hard

Fill all three blanks to create a select statement that handles sending, receiving, and default case on a channel.

Go

select {
case [1] <- 10:
    fmt.Println("Sent 10")
case val := <-[2]:
    fmt.Println("Received", val)
default:
    fmt.Println([3])
}

Drag options to blanks, or click blank then click option'

Ach

C"No communication"

D"Waiting"

Attempts:

3 left

💡 Hint

Common Mistakes

Using different channels for send and receive.

Not using a string literal in the default case.

The select sends 10 on channel ch, receives from ch, and prints "No communication" if neither is ready.