''' Purpose: deepen variable manipulation understanding.

    Problem: track the number of rabbits over five generations, where
             the number of rabbits doubles each generation. at the start
             there are two rabbits
'''

# first generation
generation  = 1
nbr_rabbits = 2

print( 'Generation: ', generation  )
print( 'Rabbits:    ', nbr_rabbits )

reply = input( 'Enter when ready: ' )           # waits until user enters something

# next generation
# The value of generation was already assigned a value so
# we can modify the value of the variable by saying
# hey take the old value and modify it by adding 1 (var = var + 1)
generation  = generation + 1 # old value(1) + 1
nbr_rabbits = nbr_rabbits * 2 # old value(2) of nbr_rabbits * 2

print( 'Generation: ', generation  )
print( 'Rabbits:    ', nbr_rabbits )

reply = input( 'Enter when ready: ' )           # waits until user enters something

# next generation
generation  = generation + 1 # old value (2) + 1
nbr_rabbits = nbr_rabbits * 2 # old value of nbr_rabbits (4) * 2

print( 'Generation: ', generation  )
print( 'Rabbits:    ', nbr_rabbits )

reply = input( 'Enter when ready: ' )           # waits until user enters something
# We will cover input a bit later!
# next generation
generation  = generation + 1 # old value (3) + 1
nbr_rabbits = nbr_rabbits * 2 # old value of nbr_rabbits (8) * 2

print( 'Generation: ', generation  )
print( 'Rabbits:    ', nbr_rabbits )

reply = input( 'Enter when ready: ' )           # waits until user enters something
# input statement prints whatever is in the parentheses in the screen
# and the user reply is stored as a string in the variable
# the input statement is assigned to (reply)
# so reply is assigned the string of what the user typed into the
# input in the console!
# More on this later!

# next generation
generation  = generation + 1 # old value (4) + 1
nbr_rabbits = nbr_rabbits * 2 # old value of nbr_rabbits (16) * 2

print( 'Generation: ', generation  )
print( 'Rabbits:    ', nbr_rabbits )

print('reply =', reply)
# Variables can be anything! You just can't start with a number.
# 1variable = 2 # nope!
# variable2 = 3
# variable_3 = 4
# andrew = 5
# Remember that snake case is using underscores in long variable
# names.
this_is_snake_case = 4