Queue Using List

Queue is a linear data structure. Queue has  First In First Out (FIFO) policy. In Queue elements are inserted at one end and deleted at other end. Queue does the insertion by using rear variable and deletion by using front variable. Rear value increases by one unit at insertion and Front value increases by one unit at deletion.

Source Code:

def display():
    if not MyQueue:
        print("queue is empty")
    else:
        print(MyQueue)
def insert():
    global rear
    if rear < size:
        value=int(input("enter number"))
        MyQueue.append(value)
        rear=rear+1
    else:
        print("Queue overflow!")
def delete():
    global front
    if not MyQueue:
        print("queue underflow")
    else:
        print("element deleted is %d" %MyQueue[front])
        del MyQueue[front]
def stop():
    print("you are about to terminate the program")
    exit(0)
def menulist():
    print("1.insert\n2.delete")
    print("3.display")
    print("4.exit")
def default():
    print("check your input")
MyQueue = []
rear=0
front=0
size=int(input("enter the size of queue"))
menulist()
while True:
    menu= {
    1: insert,
    2: delete,
    3: display,
    4: stop}
    option = int(input("Please enter your choice"))
    menu.get(option,default)()


Output:

Python 3.4.0 (v3.4.0:04f714765c13, Mar 16 2014, 19:24:06) [MSC v.1600 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> ================================ RESTART ================================
>>>
enter the size of queue3
1.insert
2.delete
3.display
4.exit
Please enter your choice1
enter number10
Please enter your choice1
enter number20
Please enter your choice1
enter number30
Please enter your choice3
[10, 20, 30]
Please enter your choice1
Queue overflow!
Please enter your choice2
element deleted is 10
Please enter your choice3
[20, 30]
Please enter your choice2
element deleted is 20
Please enter your choice3
[30]
Please enter your choice2
element deleted is 30
Please enter your choice3
queue is empty
Please enter your choice2
queue underflow
Please enter your choice4
you are about to terminate the program

>>>