testtask

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Task
{
    class Program
    {
        static void Main(string[] args)
        {
            DGift certificate = new DGift();
            certificate.Color = "green";
            certificate.Weight = 0.1;
            Console.WriteLine(certificate.ToString());
            ZGift broken_toy = new ZGift();
            broken_toy.Color = "white";
            broken_toy.Weight = 0.7;
            Console.WriteLine(broken_toy.ToString());
            Console.ReadKey();
        }
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Task
{
    interface IAboutGift
    {
        string ToString();
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Task
{
    class DGift: IAboutGift
    {
        private double weight; // kg
        private string color;
        public double Weight
        {
            get => this.weight;
            set => this.weight = value;
        }
        public string Color
        {
            get => this.color;
            set => this.color = value;
        }
        public override string ToString()
        {
            return $"Это добрый подарок! Его вес - {weight}, а его цвет - {color}";
        }
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Task
{
    class ZGift: IAboutGift
    {
        private double weight; // kg
        private string color;
        public double Weight
        {
            get => this.weight;
            set => this.weight = value;
        }
        public string Color
        {
            get => this.color;
            set => this.color = value;
        }
        public override string ToString()
        {
            return $"Это злой подарок! Его вес - {weight}, а его цвет - {color}";
        }
    }
}