ex21.py

def add(a, b):
    print("ADDING %d + %d" % (a, b))
    return a + b

def subtract(a, b):
    print("SUBTRACTING %d - %d" % (a, b))
    return a - b

def multiply(a,b):
    print("MULTIPLYING %d * %d" % (a, b))
    return a * b

def divide(a, b):
    print("DIVIDING %d / %d" % (a, b))
    # NOTE: In Python 2 this has a different meaning
    # Python 2 uses / and // for integer division
    # Python 3 uses / for float division and // for integer division
    # Python 2 can be made to work like Python 3, see this post:
    # http://stackoverflow.com/questions/2958684/python-division
    return a // b # We will use the integer division intended 

# Study Drill 4: This is my function that uses the formulas above
def linear(m, c, x):
    """This function will calculate the y in y = m * x + c"""
    print("LINEAR EQUATION %d * %d + %d" % (m, x, c))
    return add(multiply(m, x), c)

# Study Drill 4: Uncomment this line to use the function
#print(linear(3, 1, 4),"\n")

print("Let's do some math with just functions!")
age = add(30, 5)
height = subtract(78, 4)
weight = multiply(90, 2)
iq = divide(100, 2)

print("Age %d, Height: %d, Weight: %d, IQ: %d" % (age, height, weight, iq))

# A puzzle for the extra credit, type it in anyway.
print("Here is a puzzle.")

what = add(age, subtract(height, multiply(weight, divide(iq, 2))))

print("That becomes: ", what, "Can you do it by hand?")