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1. Predict the output of this program. ``

cpp
#include <iostream>
using namespace std;

int main() {
    int level = 2;
    int discount = 0;
    switch (level) {
        case 3:
            discount += 10;
            [[fallthrough]];
        case 2:
            discount += 5;
            [[fallthrough]];
        case 1:
            discount += 2;
            break;
        default:
            break;
    }
    cout << "discount: " << discount << "%\n";
}

``

discount: 2%discount: 5%discount: 7%discount: 17%

2. Predict the output of this program. ``

cpp
#include <iostream>
using namespace std;

int main() {
    int code = 200;
    switch (code) {
        case 200:
            cout << "OK\n";
        case 404:
            cout << "Not found\n";
            break;
        case 500:
            cout << "Server error\n";
            break;
        default:
            cout << "Other\n";
            break;
    }
}

``

OKOK, then Not foundNot foundOK, then Not found, then Other

3. Predict the output of this program. ``

cpp
#include <iostream>
#include <map>
#include <string>
using namespace std;

int main() {
    map<string, int> prices = {{"apple", 30}};
    int tea = prices["tea"];
    cout << tea << " " << prices.size() << "\n";
}

``

0 1-1 10 20 0

4. Which way of reading a std::map leaves the map unchanged when the key may be missing?

prices.find("tea"), checked against prices.end() before the value is usedprices["tea"], because [] only reads and never adds a keyprices["tea"] = 0, because assigning first makes the key safe to readprices.size(), because it reports how many keys exist

5. Why can't switch (command) be used when command is a std::string?

std::string has no == operator, so the compiler cannot match the case labelsA switch needs a default: label before it can check textA case label can hold only a char, so no switch can use text labelsA switch checks only whole-number values such as int, char, bool and enum, and a string has no single number to compare

Switch