# Queue in Python

Hey internet mates here we are going to make a python program to demonstrate working of queue in python.

```Program code:-
def cls():
print("\n" * 100)
def isEmpty(Qu):
if Qu == [] :
return True
else:
return False

def Enqueue (Qu, item):
Qu.append(item)
if len (Qu)==1:
front = rear = 6
else :
rear=len(Qu)-1
def Dequeue(Qu):
if isEmpty(Qu):
return "Underflow"
else:
item=Qu.pop(0)
if len(Qu)==0:
front=rear=None

#if it was single-element queue
return item

def Peek (Qu):
if isEmpty(Qu):
return Underflow
else:
front=0
return Qu[front]
def Display (Qu):
if isEmpty (Qu):
print("Queue Empty!")
elif len(Qu) == 1:
print(Qu[0], "<==front, rear")
else:
front =0
rear=len(Qu)-1
print(Queue[front]," <-front")
for a in range(1, rear ):
print(Qu[a])
print(Queue[rear], "<-rear")

#_main_program

queue = []
front=None
while True:
cls()
print("QUEUE OPERATIONS")
print("1. Enqueue")
print("2.Dequeue")
print("3. Peek")
print("4. Display queue")
print("5. Exit")
ch=int (input("Enter your choice ( 1-5): "))
if ch==1:
item= int(input("Enter item :"))
Enqueue (queue, item)
input("Press Enter to continue...")
elif ch==2:
item = Dequeue (queue)
if item== ("Underflow"):
print("Underflow Queue is empty!")
else:
print("Dequeue-ed item is", item)
input("Press enter to continue...")
elif ch==3:
item=Peek (queue)
if item=="Underflow":
print("Queue is empty!")
else :
print("Frontmost item is", item)
input("Press Enter to continue...")
elif ch == 4:
Display(queue)
input("Press Enter to continue...")
elif ch == 5:
break
else:
print("Invalid choice!")
input("Press Enter to continue...")
```