''' Purpose: demonstrate the power of looping
        Four examples
        -   without looping
        -   loop over the characters in a string
        -   loop over a list of words
        -   loop over a range of integers
'''

import pause

# print the letters in a user-specified string of length 5

reply = input( 'Enter a five character long string: ' )

c0 = reply[ 0 ]
c1 = reply[ 1 ]
c2 = reply[ 2 ]
c3 = reply[ 3 ]
c4 = reply[ 4 ]

print( c0 )
print( c1 )
print( c2 )
print( c3 )
print( c4 )

pause.enter_when_ready()

# but what if the user wants a string may or may not have length five?
#       problem - we don't know how many assignment and print() statements
#       to supply
#
# remedy: use a Python for loop to manipulate the characters in a string
#       one by one

reply = input( 'Enter a string: ' )

for character in reply : # character is called the iterator variable. It
                         # takes on in turn each character in string reply.
                         # The value following keyword in must be a sequence.
                         # Here reply is a string; i.e., a sequence of
                         # characters.
    print( character )   # The actions to be taken in the loop must be
                         # indented. The actions are called the body of the
                         # loop. In this example, the body of the loop is
                         # a single statement -- a print() statement.
                         # The body of the loop is run once for each character
                         # in reply.  The process is called iteration.
                         # there is nothing special about the use of variable
                         # character as the iterator variable. Python does not
                         # care what we name it -- it just requires it be a
                         # variable.  I used character as indicates to the
                         # reader what is going on.

pause.enter_when_ready()

# the for loop can also iterate over a list. let's now get some text from
# the user.

reply = input( 'Enter text: ' )

text  = reply.split()           # text is now a list of strings

print( text )

pause.enter_when_ready()

# use for loop to iterate over the strings in text

for string in text :              # string is now the iterator variable and
                                  # the sequence to examine is the list text
    string = string.capitalize()  # This statement is here just to show you
    print( string )               # that the body of loop can have more than
                                  # one statement.  Variable string will take
                                  # on each element of text one at a time. For
                                  # of those values, the body of the loop is
                                  # executed.

pause.enter_when_ready()

# another handy sequence can be gotten using range. range can create a
# sequence of integers. The basic form in specifying a range is
# range( n1, n2 ), where n1 and n2 are both integers. range( n1, n2 )
# produces the sequence of integers -- n1, n1 + 1, n1 + 2, ... n2 - 1

# let's show a for loop making use of range. we will get the arguments
# for the range from the user.

reply = input( 'Enter two integers: ' )

n1, n2 = reply.split()
n1, n2 = int( n1 ), int( n2 )

# for ranging - accumulating the sum of n1, n1 + 1, n1 + 2, ... n2 - 1.
# we will print out partial sums along the way
sum = 0

for i in range( n1, n2 ) :
    sum = sum + i
    print( sum )