wk5 - assignment 5.2.py

5.2 Write a program that repeatedly prompts a user for integer numbers until the user enters 'done'. 
Once 'done' is entered, print out the largest and smallest of the numbers. 
If the user enters anything other than a valid number catch it with a try/except and put out an appropriate message and ignore the number.
Enter the numbers from the book for problem 5.1 and Match the desired output as shown.
'

largest = None
smallest = None
while True:
        num = raw_input("Enter a number: ")
if num == "done" : break


try:
        num = int(num)
except:
        print "Invalid input"
continue

if largest is None:
        largest = num
elif largest < num:
        largest = num

if smallest is None:
        smallest = num
elif smallest > num:
        smallest = num


print "Maximum is", largest
print "Minimum is", smallest