Strings und Container der Standardbibliothek

#include <iostream>
#include <string>
#include <string_view>
#include <algorithm>

int main() {
    std::string s = "Hallo Welt";
    s += "!";
    std::cout << s << " " << s.size() << " " << s[0] << " " << s.at(1) << '\n';
    std::cout << s.substr(6, 4) << " " << s.find("Welt") << " " << (s.find("x") == std::string::npos) << '\n';
    s.replace(0, 5, "Servus");
    s.insert(s.size(), "!!");
    std::cout << s << '\n';
    std::string a = "abc", b = "abd";
    std::cout << (a < b) << (a == "abc") << ' ' << a + b << '\n';
    std::transform(a.begin(), a.end(), a.begin(), [](unsigned char c) { return std::toupper(c); });
    std::cout << a << ' ' << std::to_string(42) + "x" << ' ' << std::stoi("123") + 1 << ' ' << std::stod("2.5") * 2 << '\n';
    std::string_view sicht = s;                         // nur ansehen, nicht kopieren
    std::cout << sicht.substr(0, 6) << " " << s.starts_with("Servus") << '\n';   // C++20
    return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>

int main() {
    std::vector<int> v{5, 3, 9};
    v.push_back(1);                       // hinten anhängen (wächst automatisch)
    v.insert(v.begin() + 1, 42);          // an Position einfügen
    std::cout << v.size() << ' ' << v.front() << ' ' << v.back() << ' ' << v[2] << ' ' << v.at(3) << '\n';
    v.pop_back();
    v.erase(v.begin());                   // erstes Element löschen
    std::sort(v.begin(), v.end());
    for (int x : v) std::cout << x << ' ';
    std::cout << '\n';

    std::vector<std::string> namen{"Mia", "Tom"};
    namen.emplace_back("Zoe");            // direkt im Vektor erzeugen
    std::vector<int> nullen(5, 0);        // fünf Nullen
    std::vector<std::vector<int>> matrix(2, std::vector<int>(3, 1));
    std::cout << namen.size() << nullen.size() << matrix[1][2] << '\n';
    try { v.at(99); } catch (const std::out_of_range& e) { std::cout << "außerhalb\n"; }
    return 0;
}

#include <iostream>
#include <map>
#include <unordered_map>
#include <set>
#include <string>
#include <queue>
#include <array>

int main() {
    std::map<std::string, int> alter;                 // sortiert nach Schlüssel
    alter["Tom"] = 19;
    alter["Mia"] = 17;
    alter.insert({"Zoe", 21});
    for (const auto& [name, jahre] : alter) std::cout << name << '=' << jahre << ' ';
    std::cout << '\n';
    if (auto it = alter.find("Mia"); it != alter.end()) std::cout << "gefunden " << it->second << '\n';
    std::cout << alter.count("Max") << alter.contains("Tom") << '\n';     // contains: C++20

    std::unordered_map<char, int> haeufig;
    for (char c : std::string("mississippi")) haeufig[c]++;
    std::cout << haeufig['s'] << haeufig['i'] << haeufig['p'] << '\n';

    std::set<int> menge{3, 1, 3, 2};
    std::cout << menge.size() << ' ' << *menge.begin() << '\n';

    std::priority_queue<int> pq;
    for (int x : {5, 1, 8, 3}) pq.push(x);
    std::cout << pq.top() << '\n';

    std::array<int, 3> fest{1, 2, 3};
    std::cout << fest.size() << fest[1] << '\n';
    return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <list>

int main() {
    std::vector<int> v{4, 8, 15, 16, 23, 42};
    auto it = std::find(v.begin(), v.end(), 15);
    std::cout << (it - v.begin()) << ' ' << *it << '\n';
    v.erase(std::remove_if(v.begin(), v.end(), [](int x) { return x % 2; }), v.end());    // Erase-Remove-Idiom
    for (int x : v) std::cout << x << ' ';
    std::cout << '\n';
    std::cout << std::reduce(v.begin(), v.end()) << ' ' << std::accumulate(v.begin(), v.end(), 1, [](int a, int b) { return a + b / 2; }) << '\n';
    std::reverse(v.begin(), v.end());
    std::list<int> l(v.begin(), v.end());
    std::cout << l.front() << l.back() << '\n';
    std::erase_if(v, [](int x) { return x > 30; });                     // C++20: kürzer
    std::cout << v.size() << '\n';
    return 0;
}