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How to write commands for File/Json

Below is the code I made but I don't know where to start.
I will be grateful for the hint.
I have no idea what i should do next..
I want to make a program that will have a few commands.
Adding a new planet
Planet Removal
Show the List
Save to JSON
displays planet data
public class MyDate
{
public int masa { get; set; }
public int sredni { get; set; }
}
public class Lad
{
public string PlanetName { get; set; }
public MyDate Szczegoly { get; set; }
}
class Program
{
static void Main()
{
string choice = Console.ReadLine();
//string choiceup = choice.ToUpper();
switch (choice)
{
case "Add":
Add();
return;
case "Save":
break;
case "List":
LoadList();
break;
case "Exit":
return;
}
}
public static void Add()
{
Console.WriteLine("Podaj nazwe planety");
string name = Console.ReadLine();
Console.WriteLine("Podaj mase");
int masa = Convert.ToInt16(Console.ReadLine());
Console.WriteLine("Podaj srednice");
int sred = Convert.ToInt16(Console.ReadLine());
List<Lad> _data = new List<Lad>();
_data.Add(new Lad()
{
PlanetName = name,
Szczegoly = new MyDate
{
masa = masa,
sredni = sred
}
});
var json = System.Text.Json.JsonSerializer.Serialize(_data);
Console.WriteLine(json);
string json2 = JsonConvert.SerializeObject(_data, Formatting.Indented);
File.AppendAllText(#"tescikkk.json", json2);
}
static List<Lad> LoadList()
{
string text = File.ReadAllText(#"tescikkk.json");
if (string.IsNullOrEmpty(text))
return new List<Lad>() { };
return JsonConvert.DeserializeObject<Lad[]>(text).ToList();
}
}

Trying to figure out how to access list in a different method

This is my Code inside my Class. I'm trying to figure out how to access Questions list in DisplayQuestion. I have a program.cs that display a menu for a quiz and I can't have anything static.
public string Question { get; set; }
public List<string> Choices { get; set; }
public char[] CorrectChoice = { 'A', 'B', 'C', 'D' };
public List<string> Questions { get; set; }
These are my methods inside my class. I will need to access this list multiple times inside this class.
public void NewQuestion()
{
Questions = new List<string>();
Choices = new List<string>();
Console.WriteLine("Enter the question: ");
Questions.Add(Console.ReadLine());
Console.WriteLine("Enter Choice 1 for the question:");
Choices.Add(Console.ReadLine());
Console.WriteLine("Enter Choice 2 for the question: ");
Choices.Add(Console.ReadLine());
Console.WriteLine("Enter Choice 3 for the question: ");
Choices.Add(Console.ReadLine());
Console.WriteLine("Enter Choice 4 for the question:");
Choices.Add(Console.ReadLine());
// Console.WriteLine("Enter the correct choice(A,B,C,D)");
foreach (string choice in Choices)
{
Console.WriteLine();
Console.WriteLine(choice);
}
}
public void DisplayQuestions()
{
foreach(string question in Questions)
{
Console.WriteLine();
Console.WriteLine(question);
}
}

try declaring and initializing it to null in the global section or create a class with proper getter setter methods for it.

Don't feel constrained to do everything in one class. Even a rough, verbose attempt at separating concerns into separate classes helps with readability, maintainability, and sanity. Then, you're just a thoughtful refactor away from good code.
You are using C#, an OBJECT-oriented language. So go with the grain and embrace using objects.
using System;
using System.Collections.Generic;
using System.Linq;
namespace Quiz_StackOverflow
{
class Program
{
static void Main(string[] args)
{
var quizGenerator = new QuizGenerator();
var quiz = quizGenerator.GenerateQuiz();
var quizProctor = new QuizProctor();
var grade = quizProctor.ProctorQuiz(quiz);
Console.WriteLine(grade.ToString());
Console.WriteLine("Done. Press any key to exit.");
Console.ReadKey();
}
}
public class QuizGenerator
{
public Quiz GenerateQuiz()
{
var problems = GenerateProblems();
var quiz = new Quiz()
{
Problems = problems
};
return quiz;
}
private List<Problem> GenerateProblems()
{
List<Problem> problems = new List<Problem>();
int numChoices = InputValidator.GetPositiveNumber("Enter number of problems: ");
for (int i = 0; i < numChoices; i++)
{
Problem problem = GenerateProblem();
problems.Add(problem);
}
return problems;
}
private Problem GenerateProblem()
{
var question = GenerateQuestion();
var choices = GenerateChoices();
var answer = GenerateAnswer(choices);
var problem = new Problem()
{
Question = question,
Choices = choices,
Answer = answer
};
return problem;
}
private string GenerateQuestion()
{
Console.WriteLine("Enter the question: ");
string question = Console.ReadLine();
return question;
}
private List<string> GenerateChoices()
{
List<string> choices = new List<string>();
int numChoices = InputValidator.GetPositiveNumber("Enter number of choices for the question: ");
for (int i=1; i<=numChoices; i++)
{
string choice = GenerateChoice(i);
choices.Add(choice);
}
return choices;
}
private string GenerateChoice(int index)
{
Console.WriteLine($"Enter Choice {index} for the question: ");
string choice = Console.ReadLine();
return choice;
}
private Answer GenerateAnswer(List<string> choices)
{
Console.WriteLine("Enter the answer: ");
string userChoice = InputValidator.GetUserChoice(new Problem() { Choices=choices });
var answer = new Answer()
{
Value = userChoice
};
return answer;
}
}
public class QuizProctor
{
public Grade ProctorQuiz(Quiz quiz)
{
var answers = new List<Answer>();
foreach(Problem problem in quiz.Problems)
{
Answer answer = ProctorProblem(problem);
answers.Add(answer);
}
Grade grade = quiz.Grade(answers);
return grade;
}
private Answer ProctorProblem(Problem problem)
{
string userChoice = InputValidator.GetUserChoice(problem);
var answer = new Answer()
{
Value = userChoice
};
return answer;
}
}
public class Quiz
{
public List<Problem> Problems { get; set; }
public Grade Grade(List<Answer> answers)
{
List<Answer> answerKey = Problems.Select(x => x.Answer).ToList();
var rawResults = new List<Tuple<Answer, Answer>>();
for(int i=0; i<answers.Count; i++)
{
Answer correct = answerKey[i];
Answer provided = answers[i];
rawResults.Add(new Tuple<Answer, Answer>(correct, provided));
}
return new Grade(rawResults);
}
}
public class Grade
{
private List<Tuple<Answer, Answer>> RawResults { get; set; }
public decimal Percent
{
get { return decimal.Divide(RawResults.Count(x => x.Item1.Equals(x.Item2)), RawResults.Count); }
}
public Grade(List<Tuple<Answer, Answer>> rawResults)
{
RawResults = rawResults;
}
public override string ToString()
{
return string.Format("You scored a {0:P2}.", Percent);
}
}
public class Problem
{
public string Question { get; set; }
public List<string> Choices { get; set; }
public Answer Answer { get; set; }
public string Prompt()
{
Func<int, char> numberToLetter = (int n) =>
{
return (char)('A' - 1 + n);
};
string prompt = Question;
for (int i=0; i<Choices.Count; i++)
{
string choice = Choices[i];
prompt += $"\n{numberToLetter(i+1)}) {choice}";
}
return prompt;
}
}
public class Answer
{
public string Value { get; set; }
public override string ToString()
{
return Value + "";
}
public override bool Equals(object obj)
{
if (obj == null || GetType() != obj.GetType())
{
return false;
}
return (obj as Answer).Value.Equals(Value);
}
public override int GetHashCode()
{
return Value.GetHashCode();
}
}
public static class InputValidator
{
public static int GetPositiveNumber(string prompt)
{
int number = -1;
while (number < 0)
{
Console.Write(prompt);
string input = Console.ReadLine();
try
{
number = int.Parse(input);
}
catch (Exception)
{
Console.WriteLine("ERROR: Please input a positive number.");
}
}
return number;
}
public static string GetUserChoice(Problem problem)
{
Func<char, int> letterToNumber = (char c) =>
{
if (char.IsLower(c))
{
return (int)(c - 'a' + 1);
}
return (int)(c - 'A' + 1);
};
char userChoiceLetter = '_';
while (!char.IsLetter(userChoiceLetter))
{
Console.WriteLine(problem.Prompt());
Console.Write("Answer: ");
var input = Console.ReadLine();
try
{
userChoiceLetter = char.Parse(input);
}
catch (Exception)
{
Console.WriteLine("ERROR: Please input a letter corresponding to your choice.");
}
}
int answerIndex = letterToNumber(userChoiceLetter) - 1;
return problem.Choices[answerIndex];
}
}
}

Sorting a list of names with first/last name and age C#

I want to sort the names on this list first by age (which I have done so far), but I was wondering how I could then sort these names again by last name before printing to a new file. For example if I have 5 people that are 20 years old with different last names, how could I make sure those 5 people are in ascending alphabetical order?
class Person : IComparable
{
string vorname;
string nachname;
int age;
public Person(string vorname, string nachname, int age)
{
this.age = age;
this.nachname = nachname;
this.vorname = vorname;
}
public int CompareTo(object obj)
{
Person other = (Person)obj;
int a = this.age - other.age;
if (a != 0)
{
return -a;
}
else
{
return age.CompareTo(other.age);
}
}
public override string ToString()
{
return vorname + " " + nachname + "\t" + age;
}
}
class Program
{
static void Main(string[] args)
{
Person[] peeps = new Person[20];
try
{
StreamReader sr = new StreamReader("inputNames.txt");
int count = 0;
while (!sr.EndOfStream)
{
string data = sr.ReadLine();
Console.WriteLine();
string[] info = data.Split(',');
peeps[count] = new Person(info[0], info[1], int.Parse(info[2]));
count++;
}
Array.Sort(peeps);
sr.Close();
}
catch(FileNotFoundException e)
{
Console.WriteLine(e.Message);
}
StreamWriter sw = new StreamWriter("outputNames.txt");
Console.WriteLine();
foreach (Person p in peeps)
{
Console.WriteLine(p);
sw.WriteLine(p);
}
sw.Close();
}
}

Linq is your friend. You can re-write all that code in 1 line:
peeps.OrderBy(x => x.Age).ThenBy(x => x.LastName);
That's all there is to it :). You can get rid of all that IComparable junk, that's old school.
EDIT: for IComparable, you can do:
public int CompareTo(object obj)
{
Person other = (Person)obj;
if (age < other.age)
return -1;
if (String.Compare(vorname, other.vorname) < 0)
return -1;
return 1;
}
Seems to work for my quick testing, but test it more :).

You can use Linq:
people.OrderBy(person => person.age)
.ThenBy(person => person.LastName);

Little bit old-fashioned, but still. You can use Comparers and use them later as you wish for flexibility:
public class AgeComparer: Comparer<Person>
{
public override int Compare(Person x, Person y)
{
return x.Age.CompareTo(y.Age);
}
}
public class LastNameThenAgeComparer: Comparer<Person>
{
public override int Compare(Person x, Person y)
{
if (x.LastName.CompareTo(y.LastName) != 0)
{
return x.LastName.CompareTo(y.LastName);
}
else (x.Age.CompareTo(y.Age) != 0)
{
return x.Age.CompareTo(y.Age);
}
}
}
//// other types of comparers
Usage:
personList.Sort(new LastNameThenAgeComparer());

LINQ + Extension Methods
class Program
{
static void Main(string[] args)
{
try
{
"inputNames.txt".ReadFileAsLines()
.Select(l => l.Split(','))
.Select(l => new Person
{
vorname = l[0],
nachname = l[1],
age = int.Parse(l[2]),
})
.OrderBy(p => p.age).ThenBy(p => p.nachname)
.WriteAsLinesTo("outputNames.txt");
}
catch (Exception e)
{
Console.Error.WriteLine(e.Message);
}
}
}
public class Person
{
public string vorname { get; set; }
public string nachname { get; set; }
public int age { get; set; }
public override string ToString()
{
return string.Format("{0} {1}\t{2}", this.vorname, this.nachname, this.age);
}
}
public static class ToolsEx
{
public static IEnumerable<string> ReadFileAsLines(this string filename)
{
using (var reader = new StreamReader(filename))
while (!reader.EndOfStream)
yield return reader.ReadLine();
}
public static void WriteAsLinesTo(this IEnumerable lines, string filename)
{
using (var writer = new StreamWriter(filename))
foreach (var line in lines)
writer.WriteLine(line);
}
}

This is how I would implement such a person class with some comments.
//sort a person object by age first, then by last name
class Person : IComparable<Person>, IComparable
{
public string LastName { get; }
public string FirstName { get; }
public int Age { get; }
public Person(string vorname, string nachname, int age)
{
LastName = vorname;
FirstName = nachname;
Age = age;
}
// used by the default comparer
public int CompareTo(Person p)
{
// make sure comparable being consistent with equality; this will use IEquatable<Person> if implemented on Person hence better than static Equals from object
if (EqualityComparer<Person>.Default.Equals(this, p)) return 0;
if (p == null)
throw new ArgumentNullException(nameof(p), "Cannot compare person with null");
if (Age.CompareTo(p.Age) == 0)
{
return LastName.CompareTo(p.LastName);
}
return Age.CompareTo(p.Age);
}
// explicit implementation for backward compatiability
int IComparable.CompareTo(object obj)
{
Person p = obj as Person;
return CompareTo(p);
}
public override string ToString() => $"{LastName} {FirstName} \t {Age}";
}

Checking if A objects property exist

I was wanted to ask a question cause I can't really find what I'm looking for online. I want to see/check if a student IdNum already exist for example.
I don't know the right term that I'm looking for to google it, and the book I have isn't really that useful as to what to do when needing to do this sort of check.
Here is the code what i have been tried so far :
static void Main(string[] args)
{
Class1[] c1 = new Class1[10]
for (int i = 0; i < c1.Length; i++)
{
Console.WriteLine("enter Student ID");
string text = Console.ReadLine();
int value;
while (!Int32.TryParse(text, out value))
{
Console.WriteLine("ID Was not a Valid ID Number. Try Again");
text = Console.ReadLine();
}
// maybe here say if IdNum exist or not
{
// Try a different number
}
}
}
Class Class1
{
public int IdNum { get; set; }
public int SomethingElse { get; set; }
// and so on
}
Thanks

IEnumerable<Class1> c1 = GetStudents();
string text = Console.ReadLine();
int value;
while (!Int32.TryParse(text, out value))
{
Console.WriteLine("ID Was not a Valid ID Number. Try Again");
text = Console.ReadLine();
}
bool exist = c1.Any(s = > s.IdNum == value);
If you don't want to use linq, you can just rewrite the last line with:
bool exist = false;
foreach (var s in c1)
{
if (s.IdNum == value)
{
exist = true;
break;
}
}

find an object's property and get its value - C#

say there is a class like
class phones
{
public int Id {get; set;}
public string Name {get; set;}
public string Color {get; set;}
public decimal Price {get; set;}
}
List<phones> myList = GetData();
//list is filled with objects
Now, I know the Id and the exact name of the object's property and want to get the value from the matching object.
private string GetValue(int pid, string featurename)
{
string val = "";
foreach(phones obj in myList)
{
if(obj.Id == pid)
{
//if featurename is 'Name', it should be
//val = obj.Name;
//if featurename is 'Price', it should return
//val = obj.Price;
break;
}
}
return val;
}
Is this possible. Please advise.

Use this:
Phones phones= new Phones();
string returnValue = phones.GetType().GetProperty(featureName).GetValue(phones, null).ToString();
Also, remember to add validation for input featureName and error handling.

How about this:
foreach(phones obj in myList)
{
if(obj.Id == pid)
{
if (featurename == "Name")
{
return obj.Name;
}
else if (featurename == "Price")
{
return obj.Price.ToString();
}
else
{
return string.Empty;
}
}
}

I think you want Property with given featurename and use it
you could use lambda expression like this
or
Use PropertyInfo like this
foreach (PropertyInfo p in typeof(ClassName).GetProperties())
{
string propertyName = p.Name;
//....
}