using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Trip days over 12 month period");

        DateTime firstStart = new DateTime(2022, 02, 19);

        DateTime firstEnd = new DateTime(2022, 07, 16);

        double days = (firstEnd - firstStart).TotalDays;

        Console.WriteLine("days:" + days);

​

        DateTime secondStart = new DateTime(2023, 02, 05);

        DateTime secondEnd = new DateTime(2023, 06, 25);

        DateTime step = firstStart;

        while (step < firstEnd)

        {

            double daysFirst = (firstEnd - step).TotalDays;

            DateTime step1y = step.AddYears(1);

            DateTime calcSecondEnd = secondEnd > step1y ? step1y : secondEnd;

            //double daysSecond = secondEnd > step1y ? (calcSecondEnd - step1y).TotalDays : 0;

            //double daysSecond = secondEnd > step1y ? (calcSecondEnd - secondStart).TotalDays : 0;

            double daysSecond = (calcSecondEnd - secondStart).TotalDays;

            double totalDays = daysFirst + daysSecond;

            Console.WriteLine("Days from: " + step.ToString("yyyy-MM-dd")+ " -> " + totalDays + " daysFirst:" + daysFirst + " daysSecond:"+daysSecond);

            step = step.AddDays(1);

        }

    }

}