cpp_prac/demos/map_and_set.cpp

#include <iostream>
using std::cin;
using std::cout;
using std::endl;
#include <map>
#include <set>

void test_map() {
    std::map<std::string, int> msi;

    msi.insert(std::make_pair("Kalle", 1));
    msi.emplace("Lisa", 2);
    msi["Kim"] = 3;

    for (const auto &a : msi) {
        cout << a.first << " : " << a.second << endl;
    }

    cout << "Kim --> " << msi.at("Kim") << endl;
    cout << "Lisa --> " << msi["Lisa"] << endl;
    cout << "Hans --> " << msi["Hans"]
         << endl; // [] default-konstruerar ett värde
                  // för nycklar som inte finns
    try {
        cout << "Nisse --> " << msi.at("Nisse") << endl;
    } catch (std::out_of_range &e) {
        cout << "Nisse not found: " << e.what() << endl;
    }
    const auto &kim = msi.find("Kim");
    if (kim != msi.end()) {
        cout << "Kim : " << kim->second << endl;
    } else {
        cout << "Kim not found\n";
    }
    auto nisse = msi.find("Nisse");
    if (nisse != msi.end()) {
        cout << "Nisse : " << nisse->second << endl;
    } else {
        cout << "Nisse not found\n";
    }
}

void test_set() {
    std::set<int> ints{1, 3, 7};

    ints.insert(5);

    for (auto x : ints) {
        cout << x << " ";
    }
    cout << endl;

    auto has_one = ints.find(1);

    if (has_one != ints.end()) {
        cout << "one is in the set\n";
    } else {
        cout << "one is not in the set\n";
    }

    if (ints.count(1)) {
        cout << "one is in the set\n";
    } else {
        cout << "one is not in the set\n";
    }

    auto has_two = ints.find(2);

    if (has_two != ints.end()) {
        cout << "two is in the set\n";
    } else {
        cout << "two is not in the set\n";
    }

    if (ints.count(2)) {
        cout << "two is in the set\n";
    } else {
        cout << "two is not in the set\n";
    }

    auto has_five = ints.find(5);

    if (has_five != ints.end()) {
        cout << "five is in the set\n";
    } else {
        cout << "five is not in the set\n";
    }

    ints.erase(5);

    auto has_five_now = ints.find(5);

    if (has_five_now != ints.end()) {
        cout << "five is in the set\n";
    } else {
        cout << "five is not in the set\n";
    }
}

void test_set_bounds() {
    std::set<int> ints{9, 1, 3, 7, 5};

    auto lb3 = ints.lower_bound(3);
    cout << "lb3: " << *lb3 << endl;
    auto ub3 = ints.upper_bound(3);
    cout << "ub3: " << *ub3 << endl;
    auto lb4 = ints.lower_bound(4);
    cout << "lb4: " << *lb4 << endl;
    auto ub4 = ints.upper_bound(4);
    cout << "ub4: " << *ub4 << endl;
    auto er = ints.equal_range(7);
    if (er.first == er.second) {
        cout << "er.first == er.second";
    }
    cout << ", er.first: " << *er.first << ", er.second: " << *er.second
         << endl;
}

int main() {
    test_map();
    test_set();
    test_set_bounds();
}