Lab 10  While Loops

Task 1, User input with a sentinel:

Having a special value to enter to mark the end of input is a common technique in programming.  To do this one has to have something to use for the sentinel which could not be another set of input. 

• Inside of a while loop  the user is prompted to enter a non-negative number and told that he/she should enter -1 when done.
• The program tests to see if the number entered is either even or odd. Hint:  How can you test this property using the % operator?
• Even numbers are placed in one list and odd numbers are placed in another list.  (Remember append.)
• After the user has entered the -1, the program prints the two lists.   
  

As a first easy version, just to get used to the loop, you might put all the numbers in one list, and print it at the end.

Task 2,  Time for an investment to Double :

Input an annual interest rate.  Output the number of years it takes an account to double.  It does not matter what stating value you use for the account.  $1 is fine.  Allow fractional cents in the account for simplicity.  

For example, if you start with $1 and the interest rate is .2 each year, after each year you have (1 + .2) times as much as you had the year before.  

year 1:  1.0(1 + .2) = 1.2
year 2:  1.2(1 + .2) = 1.44
year 3:  1.44(1 + .2) = 1.728
year 4:  1.728(1 + .2) = 2.0736 

so the answer you print out would be 4 years.  (This is also the amount of time for a debt to double if this is a credit card balance!)

Show your work to a TA.

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