Challenge 2: A do-while That Runs Once Despite a False Condition — Possible Solution
====================================================================

#include <stdio.h>

int main() {
    int n = 0;
    do {
        printf("This runs even though n > 0 is false.\n");
    } while (n > 0);
    return 0;
}

Output:

    This runs even though n > 0 is false.

n is 0 from the very start, so the condition n > 0 is false before the
loop ever runs -- yet the message still prints exactly once.

Why a plain while loop couldn't do this: per the chapter, while checks
its condition BEFORE the first iteration. With the same starting
condition (n > 0, and n is 0), a while (n > 0) { ... } loop would
evaluate the condition, find it false immediately, and skip the body
entirely -- it would print nothing at all. do-while's defining
difference is checking AFTER the body runs instead of before, which is
exactly why it's able to execute the body once regardless of what the
condition would have said going in.

WHY THIS WORKS AS AN ANSWER
------------------------------
This constructs a genuine case where the condition is false from the
very first evaluation (n = 0, condition n > 0), proving the body still
runs -- demonstrating the check-after behavior concretely rather than
just restating the definition -- and explains precisely why a while
loop with the identical condition would behave differently (checking
before means it never even attempts the body).