''' Purpose: considers the subltety of swapping variable values
'''

# get and echo inputs

reply  = input( 'Enter two words: ' )

# remember split() is a function that strings have that
# splits a string based on its white space

w1, w2 = reply.split()

print( 'Before swapping' )
print( 'w1 =', w1 )
print( 'w2 =', w2 )

### pause to think what has happened

print(); input( 'Enter when ready: ' ); print()

# swap the values of w1 and w2
# What did everyone try?

# What did not work?

#w1 = w2
#w2 = w1

# Why? w1 has been changed to w2 so its old value is gone

# What worked????

#remember_original_w1 = w1
#w1 = w2
#w2 = remember_original_w1

# or

#x1 = w1
#x2 = w2
#w1 = x2
#w2 = x1

w1, w2 = w2, w1

# ^^^ What? This will only work in python
# In python this means take the first value before the equals
# and save the first val after the equals to it;
# then do the same for the second values; this is called multi assignment

# w2, w1 = reply.split()
# ( Note this will also work )

### pause to think what has happened

# print results

print( 'After swapping' )

print( 'w1 =', w1 )
print( 'w2 =', w2 )