##################################queue#########################################
#!/usr/bin/env python
'use list as a queue'
#define a void list as a void queue
queue = []
#define in queue function
def enQ():
queue.append(raw_input('Enter New String: ').strip())
#define out queue function
def deQ():
#judge queue whether viod
if len(queue) == 0:
print('Can not pop from an empty queue!')
else:
print('Removed' ,queue.pop(0))
#define show queue function
def viewQ():
print(queue)
#define a dictionary to chose opration function
cmds = {'e':enQ,'d':deQ,'v':viewQ}
#define a funtion to show menu
def showMenu():
pr = '''
(E)nqueue
(D)equeue
(V)iew
(Q)uit
Enter choice:'''
#double while circle make program always run
while True:
while True:
try:
#use to print menu information and get valid choice number(no space, just one bit , lower)
choice = raw_input(pr).strip()[0].lower()
except(EOFError,KeyboardInterrupt,IndexError):
#if get a invalid value,return 'q'
choice = 'q'
print('You picked: %s '% choice)
if choice not in 'devq':
print('Invalid option, try again!')
else:
break
if choice == 'q':
break
#call functions by dictionary
cmds[choice]()
#main function
if __name__ == '__main__':
showMenu()
##################################stack######################################
#!/usr/bin/env python
'this program use list as a stack'
stack = []
def pushit():
'input stack '
stack.append(raw_input('Enter New Strings: ').strip())
def popit():
'output stack'
if len(stack) == 0:
print('Can not pop from an empty stack!')
else:
print('removed [',stack.pop(),']')
def viewStack():
print(stack)
CMDs = {'u': pushit, 'o': popit, 'v': viewStack}
def showMenu():
pr = '''
p(U)sh
p(O)p
(V)iew
(Q)uit
Enter Choice:
'''
while True:
while True:
try:
choice = raw_input(pr).strip()[0].lower()
print(choice)
except(EOFError.KeyboardInterrupt,IndexError):
choice = 'q'
print('you picked: %s ' % choice)
if choice not in 'uovq':
print('Invalid option, try again')
else:
break
if choice == 'q':
break
CMDs[choice]()
if __name__ == '__main__':
showMenu()
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