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1. Predict the output of this program. ``

cpp
#include <array>
#include <iostream>
#include <string_view>
using namespace std;

int main() {
    string_view word = "banana";
    array<int, 26> counts{};
    for (char c : word) {
        counts[c - 'a'] += 1;
    }
    for (int i = 0; i < 26; ++i) {
        if (counts[i] > 0) {
            cout << static_cast<char>('a' + i) << counts[i] << " ";
        }
    }
    cout << "\n";
}

`` What does it print?

a2 b1 n3a3 b1 n2a3 n2 b1b1 a3 n2

2. Predict the output of this program. It counts duplicates with a seen array. ``

cpp
#include <iostream>
#include <vector>
using namespace std;

int main() {
    vector<bool> seen(6, false);
    vector<int> v = {5, 2, 5, 0};
    int dups = 0;
    for (int x : v) {
        if (seen[x]) {
            ++dups;
        } else {
            seen[x] = true;
        }
    }
    cout << boolalpha << dups << " " << seen[2] << "\n";
}

`` What does it print?

2 true1 false1 true0 true

3. A SeenSet for the values 0 to 9 gets the inserts 7, 3, 7, 3 and 1, in that order. Then reset() is called. How many entries does reset() write?

2413

4. Which declaration gives a seen array that is safe for the values 1 to 100?

std::array<bool, 100> seen{};std::array<bool, 99> seen{};std::array<bool, 101> seen{};

5. In a 26-slot counts array indexed by c - 'a', the letter q uses index ____. Write the number.

Type your answer.

Counting and seen arrays