""" Purpose: demonstrate arithmetic
"""

# Name some variables and print their values
a = 20
b =  3

# you cannot have an integer or float expression with unknown variables

print( "Values of interest" )
print( "a:", a )
print( "b:", b )
print()

# Perform calculations
# all of these are variables storing the results of the computations
total        = a +  b # addition
difference   = a -  b # subtraction
product      = a *  b # multiplication
dec_quotient = a /  b # normal division
int_quotient = a // b # I call this floor division, since it just throws the remainder away
power        = a ** b # exponentiation -> a^b the carat does not work for exponentiation, only ** a ** b ** c is valid (order of operations we'll get to later)
remainder    = a %  b # remainder of division, ex. 7%2: 7/2 = 3 with a remainder of 1, so 7%2 = 1

# math never goes away, we'll be doing arithmetic for the entire semester
# these are building blocks that we'll use later to solve more interesting problems
# no calculus :)

# whitespace is ignored but can greatly help with readability

# think back to learning long division, that's where remainder comes from
# % is remainder, you have to write code to calculate percentages
# only put integers in the remainder operator this isn't math class

# order of operations - we can still use () to group -> "grouping operator"
# roots are raised to fractional powers - square root is equal to raising something to the 1/2 power
# make sure you group 1/2 if you use it as your exponent!
# [] is a list, and
# we like to take our time and not do too many things on one line

# separate calculations from the display, it will help you catch mistakes - no calculations in print() statements
# no calculations in print() statements is a style choice that we use, python doesn't care
# we aren't here to learn how to write efficient code, we're here to learn how to write code :)

# there is a round() function that we'll see soon!

# Print results
print( "Results" )

print( "a + b: ", total ) # the strings are to label and organize the output, a + b = 23 is more descriptive than 23
print( "a - b: ", difference )
print( "a * b: ", product )
print( "a / b: ", dec_quotient )
print( "a // b: ", int_quotient )
print( "a ** b:", power )
print( "a % b: ", remainder )

# variables have types, and different types of data are stored in different ways
# strings are stored in quotes, as we've seen
# "3" =/= 3 , "2" + 2 =/= 4 - numeric strings are different from integers
# floats and ints play together a lot more nicely :)
# anything in single or double quotes is a string, and python will always just spit it out as is, not parse it as code

# when doing arithmetic, any decimal will cause the output to be a decimal
# it's not sig figs, it's the data type - floats and ints are stored differently in computer memory

# every CS class you take at UVA that introduces a new language will teach you the syntax