#                                                        conditionals.py

# You need to understand boolean expressions to understand conditionals.
# If you are not familiar with them, consult [DEM].

# absolute taking one argument (apparently of type integer) retuns the
# absolute value of the given integer.  To compute the absolute value,
# it uses the conditional expression, i.e., if...else...  Both syntax
# and semantics of a conditinal expression is intuitive.
#
def absolute(x):
    if x < 0:
        return -x
    else:
        return x

print absolute(-34)

# A conditional expression can be of the cascaded if...elif... ...else...
# form, again with intuitive meaning.

def absolute(x):
    if x < 0:
        return -x
    elif x > 0:
        return x
    else:
        return 0

print "absolute(-34) = ", absolute(-34)
print "absolute(34) = ", absolute(34)
print "absolute(0) = ", absolute(0)



# Exercise 1:
#
# Write a boolean function that determines if a given speed value is within
# the legal freeway speed on I-10 outside of the city limits.  Once you define
# the function, write a piece of code that calls/uses/invokes/applies the 
# defined function and prints the computed result (true or false).



# Exercise 2:
#
# Given a score out of 100, return a letter grade for the score.  Let's assign
# the letter grade by the following table:
#
#   above 89: A
#   above 79 and below 90: B
#   above 69 and below 80: C
#   above 59 and below 70: D
#   below 60: F
#
# and call the function at least five times, each time producing a different
# letter grade.
#
# It is okay to produce the final grade as a string value, e.g., "A" for an A.


# Exercise 3:
#
# See Section 4.13 of [DEM] if you want to see more exercise problems.