Collections and repeated work

15-minute session: read for 3 minutes, trace for 3, experiment for 7, and complete the check for 2. Spend longer whenever you need.

A collection stores related values. The loop visits 1, 2, and 3, updating the total from 0 to 1, then 3, then 6. Record this trace rather than guessing. Identify the first and last valid positions in this language: Pascal can declare a 1-based array, while many other examples use zero-based containers. Add another value and update the bounds correctly. Explain what an empty collection should produce.

std::cout writes output. std::vector manages a growing sequence and releases its storage when its lifetime ends. The lab selects C++17; an example that compiles under a different standard needs its settings recorded.

#include <iostream>
#include <vector>
#include <string>
#include <cassert>

int main() {
    std::vector<int> minutes{1, 2, 3};
    int total = 0;
    for (int value : minutes) total += value;
    std::cout << total << "\n";
}

Expected result: 6

Practice and evidence

Keep three notes: your prediction, the actual result, and why they match or differ. The completion check grades understanding; the practice task builds skill.

Language reference