I am trying to implement producer-consumer where teacher will teach subjects and students will study them.In my main file,I have started goroutines:

func main(){
    w:=WhiteBoard{counter:-1}   
    var x []Student=[]Student{Student{name: "Aditya",w:&w},Student{name: "Abhinav",w:&w},Student{name: "Devansh",w:&w}}

    var t Teacher =Teacher{w:&w,subjects: []string{"Math","END"}}


    mu=new(sync.Mutex)
    wg= new(sync.WaitGroup)
    
    for _,student:=range x{
        student.attendence()
    }

    t.teach() //Teacher starts teaching ->goroutines

    //Add Student to the waitgroup
    for _,student:=range x{
        go student.w.write(student.name)  //student starts writing -> goroutines 

    }
    
    wg.Wait()
}

Whiteboard is a shared data resource from which teachers will write and students will read:

type WhiteBoard struct {
    noOfStudents int
    counter      int
    subject      string
}
func (w *WhiteBoard) write(subject string){
    mu.Lock()
    
    for w.counter!=-1{

    }

    if subject=="END"{
        defer wg.Done()
        done<-true
        w.counter++
        mu.Unlock()
        fmt.Println("Teacher is ending the class: ",subject)

        return
    }
    w.subject=subject
    fmt.Println("Teacher is teaching this subject: ",subject)
    w.counter++
    student_start<-true

    mu.Unlock()
    defer wg.Done()
}

func (w *WhiteBoard) read(name string){
    for{
        select {
            case <-done:
                defer wg.Done()
                return
            
            case <-student_start:
                fmt.Println(name+ " is studying this subject: ",w.subject)
                w.counter++

                if w.counter==w.noOfStudents{
                    w.counter=-1
                } 
        }
    }
}

Now the issue is that when i only run with 1 teacher and 1 student my output looks correct:

-> % go run main.go
Aditya  has given their attendence
Teacher is teaching this subject:  Math
Aditya is studying this subject:  Math
Teacher is ending the class:  END

But with multiple students,the gorutines get stuck and don’t exit

-> % go run main.go
Aditya  has given their attendence
Abhinav  has given their attendence
Devansh  has given their attendence
Teacher is teaching this subject:  Math
Devansh is studying this subject:  Math
//Nothing prints after this

I am not sure why this is happening??Here’s the full code- https://go.dev/play/p/z3nJZUmEiI8