Exercise 9: Manual Title Case — Possible Solution
====================================================================

sentence = "the quick brown fox"

result = ""

for i, ch in enumerate(sentence):
    if i == 0 or sentence[i - 1] == " ":
        result += ch.upper()
    else:
        result += ch

print(result)

Output:
The Quick Brown Fox

WHY THIS WORKS AS AN ANSWER
------------------------------
This is the exercise the index half of enumerate() actually earns
its keep for — i == 0 catches the very first character of the whole
string (which has no character before it to check), and
sentence[i - 1] == " " catches every character that comes
immediately after a space, which is exactly the definition of "the
first letter of a word" once the very first word is already handled
by the i == 0 case.

Every other character falls into the else branch and gets appended
unchanged — including the space characters themselves. A space is
only ever preceded by a letter in this sentence, never by another
space, so sentence[i - 1] == " " is False when i points at a space,
and it falls straight into the else branch and gets copied across
untouched, exactly as it should be.