file

class File:
    def __init__(self):
        self.valeurs=[]

    def enfiler(self,valeur):
         self.valeurs.append(valeur)

    def defiler(self):
         if self.valeurs:
             return self.valeurs.pop(0)

    def estVide(self):
        return self.valeurs==[]

    def longueur(self):
        return len(self.valeurs)

    def __str__(self):
        ch="\n Etat de la file: \n"
        for x in self.valeurs:
            ch+= str(x)+""
        return ch

q=File()
q.enfiler(9)
q.enfiler(2)
q.enfiler(5)
print(q)
q.defiler()
q.enfiler(7)
print ("la file est-t-elle vide:",q.estVide())
print(q)
print("Longuer de la file: ", q.longueur)