# L-4 MCS 260 Wed 5 Sep 2007 yield and balance computation
#
# This program prompts the user for the following inputs:
#   (1) principal , (2) annual interest rate (percentage format),
#   (3) and number of years.  (1) and (2) are floats, (3) is integer.
# The output of the program consists of
#   (1) the ending balance and (2) the yield of the investment.
#
# welcome message, read input and convert to arithmetic types
print 'computation of yield and balance'
user_input = raw_input('Give the principal : ')
principal = float(user_input)
user_input = raw_input('Give the annual interest rate : ')
interest = float(user_input)
user_input = raw_input('Give the number of years : ')
years = int(user_input)
# confirm the user input using string concatenation
confirm_principal = 'Investing ' + '$%.2f' % principal 
confirm_interest = ' at ' + '%.2f' % interest + '%'
confirm_years = ' for ' + '%d' % years + ' years'
print confirm_principal + confirm_interest + confirm_years
# calculate balance and yield (yield is a Python statement)
balance = principal * (1.0 + interest/100.0)**years
the_yield = balance - principal
# print the outcome, again using string concatenation
show_balance = '$%.2f' % balance + ' as balance'
show_yield = '$%.2f' % the_yield + ' as yield'
print 'gives ' + show_balance + ' and ' + show_yield + '.'