Exercise 2: Reverse a String, Three Ways — Possible Solution
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word = "programming"

# Version 1 — for ch in word:
reversed_word_1 = ""
for ch in word:
    reversed_word_1 = ch + reversed_word_1
print(reversed_word_1)

# Version 2 — for i in range(len(word)):
reversed_word_2 = ""
for i in range(len(word)):
    reversed_word_2 = word[i] + reversed_word_2
print(reversed_word_2)

# Version 3 — for i, ch in enumerate(word):
reversed_word_3 = ""
for i, ch in enumerate(word):
    reversed_word_3 = ch + reversed_word_3
print(reversed_word_3)

Output:
gnimmargorp
gnimmargorp
gnimmargorp

WHY THIS WORKS AS AN ANSWER
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All three versions rely on the same trick: instead of appending each
new character to the *end* of the result (which would just copy the
string back out in its original order), each one is glued onto the
*front* — ch + reversed_word instead of reversed_word + ch. Since
the loop still visits the original word from first character to
last, prepending each one means the very first character processed
("p") ends up at the very end of the result, and the very last
character processed ("g") ends up at the front.

The three versions only differ in how ch is obtained: directly from
the loop (Version 1), looked up by index (Version 2), or unpacked
from an enumerate() tuple where the index itself is never actually
used (Version 3) — a small hint that Version 3 is over-engineered
for this particular problem, since nothing here needed the index at
all. Version 1 is the most natural fit.