'''
    Purpose: counting backward using using loops
'''
n = 10

# way 1:
# range() function has a third argument called the step variable
#   it tells the range how many steps to take
#       ex: range( 0, 10, 2 ) --> only get every other number: 0, 2, 4, 6, 8
# range() also allows you to put the bigger number as the first number and the smaller number as the second number
#   but you must also put the step argument to tell the range() to go backward
#   otherwise, there are no numbers that include the bigger number and go UP to but not including the smaller
#       second number
#       ex: range( 10, 0, -1 ) --> numbers will start from 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 (doesn't include the
#           second number - always 1 more than the second number)

for i in range( n, 5, -1 ):
     print( i )

print()

# way 2

# do a subtraction accumulation with a while loop or a for loop

# accumulate a difference
difference = n
print( difference )
# for n times, each time subtract one from the difference accumulator
for i in range( 0, n ):
    difference = difference - 1
    print(difference)

print()

# way 3: use a while loop
# very similar to the for loop in way 2
# TRY IT OUT!

# way 4:
for i in range( 0, n + 1 ):
    down = n - i     # i updates from 0 to include n

    # i = 0
    # down = n - 0  --> n
    # if n = 10 --> down = 10

    # i = 1
    # down = n - 1
    # if n = 10 --> down = 9

    # i = 2
    # down = n - 2
    # if n = 10 --> down = 8

    # ...
    # i = n
    # down = n - n
    # if n = 10 --> down = 0

    print( down )

print()

# way 5
for i in reversed( range( 0, n + 1 ) ):  # get the reverse of the range 0 to n
    print( i )

print()