How do I make my code concurrent as I want

[dusk mortar]

I am learning concurrency and I want the following code to output

print in worker function
print in inner anonymous function
Done

Here is the code

package main

import (
    "fmt"
    "sync"
    "time"
)

func main() {
    var wg sync.WaitGroup
    wg.Add(2)
    go func() {
        defer wg.Done()
        go worker()
        go func() {
            defer wg.Done()
            fmt.Println("print in inner anonymous function")
        }()
    }()
    wg.Wait()
    fmt.Println("Done")
    time.Sleep(time.Second)
}

func worker() {
    fmt.Println("print in worker function")
}

[grand jetty]

The way you have set up now, there’s no guarantee that worker() will run before the inner anonymous function print will

[dusk mortar]

How should I set it up then

[wispy pawn]

don't use concurrency

[sudden raven]

^ lol

[grand jetty]

You don’t need that worker goroutine

[wispy pawn]

@dusk mortar if you want code to excute sequentially then you don't want concurrency

[dusk mortar]

What is the use of waitgroup then?

isn't it to wait for goroutines?

[sudden raven]

when u wanna wait for some functions to finish and then continue ur sequential code

[wispy pawn]

it alows main to wait until both workers finished to work

but it doesn't do anything for the two workers

[dusk mortar]

so I shouldn't use concurrency because I want it to be in sequency?

Ok

more like I wanted to understand how waitgroup work so I am experimenting things out

where can I understand waitgroup from?

Any recommended book/guide/document?

[queen tendon]

waitgroup means, i have 10 workers, i want to wait until they all stopped

[wispy pawn]

You are just using it for something that don't need it.

Try doing something else, for example try to download multiple URLs at once.
Create a program that accepts a list of URLs and download all of them in parallel.
It will become obvious what waitgroup do

[dusk mortar]

oh ok

I will try

Thanks guys

[queen tendon]

if you want the url to be sorted, you can make the worker pass the result into a channel to the main thread
which gets sorted before displaying(if you want sequence that's how you do it, unify everything first)

[dusk mortar]

I will try

understanding concurrency in general will take a lot of time

[wispy pawn]

this is not needed, you just need a for loop

[queen tendon]

that's assuming you want it sorted by alphanumeric for arbitrary reasons
but otherwise you could just directly for range the channel and display results as soon as they are done