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

    Something to remember: Python represents an integer as an int
'''

# ... is ellipsis (it's a placeholder that says "I will fill this in later!")

# name some values
a = 7         # integer
b = 2         # integer
c = -3         # negative integer
d = 99.9         # decimal

# ASSIGNMENT
    # Uses = to assign
    # variable/identifier = value we want to assign
        # Ex. a = 24
    # Whatever is on the left is assigned the value on the right!

print()

print( 'Values of interest' )

print()

print( 'a =', a ) # a = 7
print( 'b =', b ) # b = 2
print( 'c =', c ) # c = -3
print( 'd =', d ) # d = 99.9

# Breakdown:
# print( 'a=',       a )
#       string    variable a that holds a number value
# Gets printed as a = 7 (space in between 'a=' and 7

# You must assign the variable before you print it!
    # print(x) # Doesn't know what x is?? We didn't assign x to anything!
# print( 2, 'hello', 3.35 ) SEPARATE DIFFERENT DATA TYPES / MULTIPLE THINGS WITH COMMAS
# prints
    # 2 hello 3.35
# If you have a comma in the print statement, it will put a space between the things you want to print.

print()

reply = input( 'Enter when ready: ' )

print()

# perform and display some integer calculations
total        = a +  b   # addition
difference   = a -  b   # subtraction
product      = a *  b   # multiplication
dec_quotient = a /  b   # decimal/ "float" division
int_quotient = a // b   # integer division
remainder    = a %  b   # Remainder (modulus operator) 6%4 = 1 Remainder 2 = 2
power        = a ** b   # Exponentiation 3 ** 2 = 3 ^ 2 = 9

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 )

# IMPORTANT:
    # Python can't represent an infinite number of decimal places!
    # Floats (floating points) are decimals!
    # We can only represent a finite number of decimals places!
    # Python usually about 16-17 decimal places of accuracy (about 60 bits). This has shown up on previous tests :)
    # Remember that Python can't represent an infinite number of decimal places!

# DIVISION
    # / is decimal division
    # // is integer division (it chops off the decimal part of your division!)
    # 3/2 = 1.5 (decimal)
    # 3//2 = 1.5 = 1 (integer)
print()

reply = input( 'Enter when ready: ' )

print()

# introduce some other built-in functions
abs_c = abs( c )    # gives you absolute value of c
float_c = float( c )    # gives you float conversion of c
int_d = int( d )        # gives you integer conversion of d

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

print()