using System;

public class Program

{

    public static void Main()

    {

        double price = 12.456;

        string name = "Lorem Ipsum";

        DateTime paidOn = new DateTime(2018, 1, 1, 12, 34, 56);

        // instead of doing this

        string normal = name + " paid " + price.ToString("0.00") + " on " + paidOn.ToString("yyyy-MM-dd HH:mm:ss");

        // you can do this

        string interpolated = $"{name} paid {price:0.00} on {paidOn:yyyy-MM-dd HH:mm:ss}";

        Console.WriteLine(normal);

        Console.WriteLine(interpolated);

        // 00.00 -> numbers are formatted into 2 decimal places, padded with zeros

    }

}