x004.h

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#pragma once
#include "xunits.h"
#include <cmath>
#include <iomanip>
#include <iostream>
#include <stdexcept>
#include <vector>

namespace nmx::apps::x004 {

inline double read_input(const char *c) {
    double x;
    std::cout << c << "=?\t";
    std::cin >> x;
    // x ist double, std::cin erwartet double
    if (std::cin.fail()) {
        throw std::invalid_argument(c);
    }
    // die Seite eines Dreiecks muss immer eine positive Zahl sein
    if (x <= 0) {
        throw std::domain_error(c);
    }
    return x;
};

inline void ex1() {
    constexpr auto maxstreamsize = std::numeric_limits<std::streamsize>::max();
    char cmd = 'y';

    // rechne bis der Benutzer per Befehl das Programm beendet
    while (cmd == 'y') {
        try {
            //Benutzereingabe: zwei senkrechte Seiten
            double x = read_input("x");
            double y = read_input("y");
            //Ausgabe
            std::cout << "hypotenuse:" << std::hypot(x, y) << std::endl;
        } catch (std::invalid_argument &invarg) {
            //Buchstabe statt einer Zahl wurde eingegeben
            std::cin.clear();
            //ignoriere alle restlichen Eingaben
            std::cin.ignore(maxstreamsize, '\n');
            std::cout << "invalid argument for:" //
                      << invarg.what() << std::endl;
        } catch (std::domain_error &domerr) {
            //negative Zahl wurde eingegeben
            std::cin.clear();
            //ignoriere alle restlichen Eingaben
            std::cin.ignore(maxstreamsize, '\n');
            std::cout << "input parameter must be >0:" //
                      << domerr.what() << std::endl;
        }

        //Programm beenden?
        do {
            std::cout << "new claculation? y[yes] / n[no]" << std::endl;
            std::cin >> cmd;
        } while (cmd != 'y' && cmd != 'n');
    }
}

inline double brake_assist(double v0, double d, double tR) {
    double x0 = v0 * tR;

    if (x0 > d) {
        throw std::range_error(std::to_string(0));
    }

    double a = 0.5 * std::pow(v0, 2) / (d - x0);
    if (a > 6) {
        throw std::range_error(std::to_string(a));
    }
    return a;
};

void break_assist_ui(double v0, double d, double rtime) {
    std::cout << "d=" << d << " m,";
    std::cout << "v0=" << v0 << " m/s,";
    std::cout << "tR=" << rtime << " m/s" << std::endl;
    std::cout << std::setprecision(2);
    try {
        const double a = brake_assist(v0, d, rtime);
        double x0 = v0 * rtime;
        double x = x0 + 0.5 * std::pow(v0, 2) / a;
        std::cout << "need a=" << a << " m/s^2" << std::endl;
        std::cout << "use a=" << std::ceil(a) << " m/s^2" << std::endl;
        std::cout << "distance=" << x << std::endl;
    } catch (std::range_error err) {
        std::cout << "need : " << err.what() << " m/s^2" << std::endl;
        std::cout << "car will crash" << std::endl;
    }
}

void ex2() {
    const double d = 30.0;
    const double rtime = 0.7;
    const double v0 = 14; //m/s;
    break_assist_ui(v0, d, rtime);
    //zweiter Versuch mit Geschwindigkeit 2*v0
    std::cout << "-------------------" << std::endl;
    break_assist_ui(2 * v0, d, rtime);
}

} // namespace nmx::apps::x004