'''  Purpose: demonstrate arithmetic and use of variables
        for naming things
'''

# name some values
a = 13
b =  5

# We are using names (variables) and assigning them values.
# So variable a (on the left) is assigned the value 13 (on the right).
# We are associating a with 13 and b with 5.
# The assignment statement is where the name of the variable is on the left
# and its value is on the right.
print( "a =", a )
print( "b =", b )

# 88 = c # error! It doesn't know what 88 is.
input()

# input() is another built in function in Python where it waits for the user
# to type something (give it input). An empty input() is just waiting for an input.
#  You have to type it in the console (the botton part where you see the output).
# display some integer calculations
# If you can't see the second part with the integer math, hit enter in the console since
# there was an input() waiting for you to type something for the next part to print (execute).
print( 'Integer arithmetic' )

total        = a +  b
difference   = a -  b
product      = a *  b
dec_quotient = a /  b # decimal division
int_quotient = a // b # integer division (result will be an int)
remainder    = a %  b # remainder (modulus) operator so the remainder produced by 13/5
power        = a ** b # exponentiation a to the b so its 13 ^ 5

# A valid name is an identifier. It needs to start with an alphabetic letter/character
# and then you can have
# numbers follow it. Soo name your variables a, a1, a23, so on but not like 2, 88.
# We will be using these numeric operators in this class for calculations!
# Python's basic types: strings, ints, floats (decimals), logical operators (True/False)
# There are an infinite number of decimals but we can't represent EVERY decimal number
# in Python. (I would remember this; it was on previous tests :))
# Python can only represent up to a certain number of bits in Python when it comes
# to floats. The digits in the float values can only reach a certain number of bits.
# You can have at most like 15 places of decimal accuracy.
# A variable is an identifier! print() is a function NOT an identifier!
# Functions are named with identifiers buttt print() itself is a function.
print(  'a + b  =', total )
print(  'a - b  =', difference )
print(  'a * b  =', product )
print(  'a / b  =', dec_quotient )
print(  'a // b =', int_quotient )
print(  'a % b  =', remainder )
print(  'a ** b =', power )

input()

# introduce some other built-in functions
print( 'Some handy functions' )
c =  -10
d = 1.75
e = -1.75

print( "c =", c )
print( "d =", d )
print( "e =", e )

input()

abs_c = abs( c )
float_c = float( c )
int_d = int( d )

print( 'abs( c )   =',  abs_c )
print( 'float( c ) =', float_c )
print( 'int( d )   =', int_d )

print()