Challenge 2: A std::map Storing Ages, With a Lookup — Possible Solution
====================================================================

#include <iostream>
#include <map>
#include <string>

int main() {
    std::map<std::string, int> ages;
    ages["Alice"] = 30;
    ages["Bob"] = 25;
    ages["Carol"] = 35;

    std::cout << ages["Bob"] << std::endl;

    return 0;
}

Output:

    25

WHY THIS WORKS AS AN ANSWER
------------------------------
Three key-value pairs are inserted using the same [] syntax the
chapter's own example demonstrates, and looking up ages["Bob"] returns
exactly the value associated with that specific key -- confirming
std::map correctly resolves the lookup, exactly the operation c3-2's
own hand-built hash table required a manual hash-and-bucket-traversal
sequence to perform, now expressed in one line.