Practice

#include <iostream>
#include <fstream>
#include <math.h>
#include <vector>
#include <string>
#include <sstream>
#include <map>

using namespace std;

class Day {
private:
    int _year;
    int _month;
    int _day_number;
    string _name;
public:
    Day(int year, int month, int day_number): _year(year),
        _month(month), _day_number(day_number) {
        _generateName();
    }

    int getDayNumber() const {
        return _day_number;
    }

    const string& getName() const {
        return _name;
    }

    bool operator<(const Day& d) const {
        return toSeconds() < d.toSeconds();

        if (_year == d._year) {
            if (_month == d._month) {
                return _day_number < d._day_number;
            }

            return _month < d._month;
        }

        return _year < d._year;
    }

    int toSeconds() const {
        return _year * 1000000 + _month * 10000 + _day_number * 10;
    }

    friend Day operator+(const Day& a, const Day& b);
    friend istream& operator>>(istream& in, Day& d);
    friend ostream& operator<<(ostream& out, const Day& d);

private:
    void _generateName() {
        vector<string> a = { "M", "T", "W", "T", "F", "S", "S" };
        _name = a[_day_number % 7];
    }
};

Day operator+(const Day& a, const Day& b) {
    Day result(b._year, a._month, a._day_number + b._day_number);
    return result;
}

istream& operator>>(istream& in, Day& d) {
    in >> d._year >> d._month >> d._day_number;
    d._generateName();
    return in;
}

ostream& operator<<(ostream& out, const Day& d) {
    out << "Year:\t" << d._year << "\n";
    out << "Month:\t" << d._month << "\n";
    out << "Day number: " << d._day_number << "\n";
    out << "Name:\t" << d._name << "\n\n";

    return out;
}

struct Time {
    int hour;
    int mins;
    int seconds;

    int toSeconds() const {
        return hour * 3600 + mins * 60 + seconds;
    }

    bool operator<(const Time& t2) const {
        return toSeconds() < t2.toSeconds();
    }
};

struct Earthquake {
    double lat;
    double lon;
    double depth;
    double magnitude;
    string location;
};

// 23:59:23
istream& operator>>(istream& in, Time& t) {
    string s;
    getline(in, s, ':');
    t.hour = stoi(s);
    getline(in, s, ':');
    t.mins = stoi(s);
    getline(in, s);
    t.seconds = stoi(s);

    return in;
}


void fillMap(std::multimap<Time, Earthquake>& m) {
    ifstream input("earthquakes.csv");

    if (!input.is_open()) {
        cout << "Error.\n";
        return;
    }

    string s;
    getline(input, s);

    while (getline(input, s)) {
        Time t;
        Earthquake e;
        istringstream s_stream(s);

        getline(s_stream, s, ',');
        // s = "23:57:33"
        istringstream s_stream2(s);
        s_stream2 >> t;

        getline(s_stream, s, ',');
        e.lat = stod(s);

        getline(s_stream, s, ',');
        e.lon = stod(s);

        getline(s_stream, s, ',');
        e.depth = stod(s);

        getline(s_stream, s, ',');
        e.magnitude = stod(s);

        getline(s_stream, s);
        e.location = s;

        m.insert({t, e});
    }

    input.close();
}

void queryEarthquakes(std::multimap<Time, Earthquake>& m,
                      const Time& tstart, const Time& tend,
                      std::string x) {
    auto start = m.lower_bound(tstart);
    for (; start != m.end() && start->first < tend; ++start) {
        if (start->second.location.find(x) != string::npos) {
            cout << start->second;
        }
    }
}

int main() {

    multimap<Day, int> mp;
    Day d(1980, 90, 3);
    Day d2(1981, 90, 3);

    mp.insert({d, 3});
    mp.insert({d, 4});
    mp.insert({d2, 4});

    cout << "Before:\n";
    for (auto& x : mp) {
        cout << x.first << " " << x.second << "\n";
    }

    mp.erase(mp.find(d));

    cout << "After:\n";
    for (auto& x : mp) {
        cout << x.first << " " << x.second << "\n";
    }

    return 0;

    ifstream input("earthquakes.csv");

    string s;
    getline(input, s);

    while (getline(input, s)) {
        cout << s << "\n";
        istringstream s_stream(s);
        getline(s_stream, s, ':');
        cout << s << " | ";
        getline(s_stream, s, ',');
        cout << s << " | ";
        getline(s_stream, s, ',');
        cout << s << " | ";
        getline(s_stream, s, ',');
        cout << s << " | \n";
    }

    input.close();
    return 0;
}