using System;

using System.Collections.Generic;

using System.Text;

using System.Reflection;

​

public class Program

{

    public static void Main(string[] args)

    {

        var person = new Person("John Doe", 30, true, new List<string> { "C#", "ASP.NET", "SQL" });

        // Serialize the object

        var serializer = new SimpleJSONSerializer();

        string json = serializer.Serialize(person);

        Console.WriteLine(json);

    }

​

    public class Person

    {

        public string Name { get; set; }

        public int Age { get; set; }

        public bool IsEmployee { get; set; }

        public List<string> Skills { get; set; }

​

        public Person(string name, int age, bool isEmployee, List<string> skills)

        {

            Name = name;

            Age = age;

            IsEmployee = isEmployee;

            Skills = skills;

        }

    }

​

    public class SimpleJSONSerializer

    {

        public string Serialize(object obj)

        {

            if (obj == null)

                return "null";

            StringBuilder json = new StringBuilder();

            Type type = obj.GetType();

            var properties = type.GetProperties(BindingFlags.Public | BindingFlags.Instance);

            json.Append("{");

            bool first = true;

            foreach (var property in properties)

            {

                if (!first)

                {

                    json.Append(", ");

                }

​

                first = false;

                // Append Key

                json.Append($"\"{property.Name}\": ");

                // Append value

                var value = property.GetValue(obj);

                json.Append(SerializeValue(value));

            }

​

            json.Append("}");

            return json.ToString();

        }

​

        private string SerializeValue(object value)

        {

            if (value == null)

                return "null";

            Type valueType = value.GetType();

            if (valueType == typeof(string))

            {

                return $"\"{EscapeString((string)value)}\"";

            }

            else if (valueType == typeof(bool))

            {

                return value.ToString().ToLower(); // JSON expects `true` and `false`

            }

            else if (valueType.IsPrimitive || value is decimal)

            {

                return value.ToString();

            }

            else if (value is IEnumerable<object> enumerable)

            {

                StringBuilder arrayJson = new StringBuilder();

                arrayJson.Append("[");

                bool first = true;

                foreach (var item in enumerable)

                {

                    if (!first)

                    {

                        arrayJson.Append(", ");

                    }

​

                    first = false;

                    arrayJson.Append(SerializeValue(item));

                }

​

                arrayJson.Append("]");

                return arrayJson.ToString();

            }

            else // Complex type

            {

                return Serialize(value); // Recursive serialization

            }

        }

​

        private string EscapeString(string value)

        {

            StringBuilder escapedString = new StringBuilder();

            foreach (char c in value)

            {

                if (c == '\\' || c == '"')

                {

                    escapedString.Append('\\').Append(c);

                }

                else

                {

                    escapedString.Append(c);

                }

            }

​

            return escapedString.ToString();

        }

    }

}