Goroutine lifecycle - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a new goroutine that prints "Hello".

Go

go [1]()

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

APrintHello

Bfmt.Println

Chello

DprintHello

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting parentheses after the function name

Using a variable name instead of a function

Not using the go keyword

The go keyword starts a new goroutine. You need to call a function, here PrintHello, to run concurrently.

2fill in blank

medium

Complete the code to wait for a goroutine to finish using a channel.

Go

done := make(chan bool)
go func() {
    // do work
    done[1]true
}()
<-done

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

A->

B<-

C=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using = instead of <- to send to channel

Using -> which is invalid syntax

Using == which is a comparison operator

To send a value into a channel, use the <- operator pointing to the channel: done <- true.

3fill in blank

hard

Fix the error in the code that launches a goroutine with a loop variable.

Go

for i := 0; i < 3; i++ {
    go func([1] int) {
        fmt.Println([1])
    }(i)
}

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

Aindex

B0

Cj

Di

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different variable name not defined

Not passing the loop variable to the goroutine

Expecting goroutines to capture loop variable automatically

The loop variable i must be passed as a parameter to the goroutine function to capture its current value. Without it, all goroutines print the last value.

4fill in blank

hard

Fill both blanks to create a goroutine that signals completion using a WaitGroup.

Go

var wg sync.WaitGroup
wg.[1](1)
go func() {
    defer wg.[2]()
    // work here
}()
wg.Wait()

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

AAdd

BDone

CWait

DSignal

Attempts:

3 left

💡 Hint

Common Mistakes

Using Wait instead of Add to set count

Forgetting to call Done inside goroutine

Calling Signal which is not a WaitGroup method

wg.Add(1) tells the WaitGroup to wait for one goroutine. Inside the goroutine, defer wg.Done() signals when it finishes. Finally, wg.Wait() blocks until done.

5fill in blank

hard

Fill both blanks to create a buffered channel and send/receive data correctly.

Go

ch := make(chan int, [1])
go func() {
    ch[2]42
}()
value := <-ch

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

A1

B<-

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 for buffer size which makes it unbuffered

Placing receive operator after channel name

Leaving blanks with wrong operators

The channel is created with buffer size 1. Sending uses ch <- 42. Receiving uses <- ch, but here the blank after ch is empty because the receive operator is before the channel.