Blocking behavior in Go - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to make the main goroutine wait for the other goroutine to finish.

Go

package main

import (
	"fmt"
	"sync"
)

func main() {
	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		defer wg.[1]()
		fmt.Println("Hello from goroutine")
	}()
	wg.Wait()
}

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

ADone

Bdone()

CDone()

DWait()

Attempts:

3 left

💡 Hint

Common Mistakes

Using Done() which adds extra parentheses

Using lowercase done instead of Done

Calling Wait instead of Done inside the goroutine

The WaitGroup's Done method signals that a goroutine has finished. The parentheses are already provided in the code.

2fill in blank

medium

Complete the code to send a value into the channel and block until it is received.

Go

package main

import "fmt"

func main() {
	ch := make(chan int)
	go func() {
		fmt.Println("Received:", <-ch)
	}()
	ch[1] 42
}

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

A<-

B<-chan

C<-chan<-

D<-chan<-chan

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong arrow direction

Confusing channel type syntax with send operation

To send a value into a channel, use the channel name followed by <- and the value.

3fill in blank

hard

Fix the error in the code to avoid deadlock when receiving from the channel.

Go

package main

import "fmt"

func main() {
	ch := make(chan int)
	go func() {
		ch <- 10
	}()
	value := [1]ch
	fmt.Println(value)
}

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

A<-chan

B<-

Cchan<-

Dchan

Attempts:

3 left

💡 Hint

Common Mistakes

Using channel type syntax instead of receive operator

Omitting the receive operator causing deadlock

To receive a value from a channel, use the <- operator before the channel name.

4fill in blank

hard

Fill both blanks to create a map that stores word lengths only for words longer than 3 characters.

Go

package main

import "fmt"

func main() {
	words := []string{"go", "code", "chat", "ai"}
	lengths := map[string]int{}
	for _, word := range words {
		if len(word) [1] 3 {
			lengths[word] = [2]
		}
	}
	fmt.Println(lengths)
}

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

A>

Blen(word)

C<

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using less than instead of greater than

Assigning the word instead of its length

We check if the length of the word is greater than 3, then store the length of the word.

5fill in blank

hard

Fill all three blanks to create a map of uppercase words to their lengths for words longer than 2 characters.

Go

package main

import (
	"fmt"
	"strings"
)

func main() {
	words := []string{"go", "code", "chat", "ai"}
	lengths := map[string]int{}
	for _, word := range words {
		if len(word) [1] 2 {
			lengths[[2]] = [3]
		}
	}
	fmt.Println(lengths)
}

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

A>

Bstrings.ToUpper(word)

Clen(word)

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using less than instead of greater than

Using the original word instead of uppercase

Assigning the word instead of its length

We check if the word length is greater than 2, then store the uppercase word as key and its length as value.