implemented first option

src/Ausgabenverwaltung.cpp

@@ -1,6 +1,135 @@
 #include <iostream>
+#include <list>
+#include <string>
+
+using namespace std;
+
+enum category
+{
+	None = 0,
+	Tanken = 1,
+	Nahrungsmittel = 2,
+	Reinigungsmittel = 3,
+	Urlaub = 4,
+	Haustiere = 5,
+	Bekleidung = 6,
+	Wohnen = 7,
+	Versicherung = 8
+};
+
+class Invoice
+{
+private:
+	int number_ = 0;
+	double amount_;
+	unsigned short month_ = 0;
+	category category_ = None;
+public:
+	Invoice(int number, double amount, unsigned short month, category category) : number_(number), amount_(amount),
+		month_(month), category_(category)
+	{
+	}
+
+	int get_number() const
+	{
+		return number_;
+	}
+};
+
+template <typename T>
+T ask_question(const string& question)
+{
+	cout << question << endl;
+	cout << "> ";
+	T value;
+	cin >> value;
+	return value;
+}
+
+list<Invoice> invoices;
+
+void create_invoice();
+
+void output_invoice_per_month();
+
+void output_invoice_per_category();
 
 int main()
 {
-    std::cout << "Hello World!\n"; 
+	auto end_program = false;
+	while (!end_program)
+	{
+		system("cls");
+		cout << "Ausgabenverwaltung (" << invoices.size() << " Rechnungen)" << endl << endl;
+		cout << "Bitte w\x84hlen Sie eine Option:" << endl;
+		cout << "1: Erfassung einer Rechnung (inkl. Abfrage der Rechnungsdaten)" << endl;
+		cout << "2: Alle Ausgaben, sortiert nach Monat, ausgeben" << endl;
+		cout << "3: Summe der Ausgaben pro Kategorie ausgeben" << endl;
+		cout << "4: Rechnung l\x94schen" << endl;
+		cout << "0: Programm beenden" << endl;
+		auto input = ask_question<int>("Ihre Eingabe:");
+
+		switch (input)
+		{
+		case 1:
+			create_invoice();
+			break;
+		case 2:
+			output_invoice_per_month();
+			break;
+		case 3:
+			output_invoice_per_category();
+			break;
+		case 0:
+			end_program = true;
+			break;
+		default:
+			cout << "Unerlaubte Eingabe" << endl;
+			system("pause");
+		}
+	}
+	return 0;
+}
+
+category get_category();
+
+void create_invoice()
+{
+	cout << "Eine neue Rechnung erstellen." << endl << endl;
+	auto invoice_no = invoices.empty() ? 1 : invoices.back().get_number() + 1;
+	auto amount = ask_question<double>("Bitte geben Sie den Betrag in Euro ein.");
+	auto month = ask_question<unsigned short>("Bitte geben Sie den Monat ein.");
+	const auto category = get_category();
+	const auto i = Invoice(invoice_no, amount, month, category);
+	invoices.push_back(i);
+}
+
+void output_invoice_per_month()
+{
+}
+
+void output_invoice_per_category()
+{
+}
+
+category get_category()
+{
+	while (true)
+	{
+		cout << "Bitte w\x84hlen sie eine Kategorie aus:" << endl;
+		cout << " 1: Tanken" << endl;
+		cout << " 2: Nahrungsmittel" << endl;
+		cout << " 3: Reinigungsmittel" << endl;
+		cout << " 4: Urlaub" << endl;
+		cout << " 5: Haustiere" << endl;
+		cout << " 6: Bekleidung" << endl;
+		cout << " 7: Wohnen" << endl;
+		cout << " 8: Versicherung" << endl;
+		auto cat = ask_question<int>("");
+		if (cat > 0 && cat <= 8)
+		{
+			return static_cast<category>(cat);
+		}
+		cout << "Ung\x81ltige Eingabe";
+	}
 }