# File: roundoff.py
# Demonstrate round-off error
#
# Matt Bishop, ECS 10, Spring 2014
#
# First, set x to 1.0 and print it
x = 0.1
print("This should print the value of x as 0.1:", x)
#
# Now, add x to itself 10 times and print the value
y = x + x + x + x + x + x + x + x + x + x
print("This should print 1.0, the value of x added to itself 10 times:", y)
#
# Now compare it to 1.0 -- note it's not the same!
print("Now compare y to 1.0:", y == 1.0)
#
# And here's why -- go out to 20 decimal places
print("The actual value of y, to 20 places:", "%.20f" % y)