using System;

var now = DateTime.Now;
var yesterday = now.AddDays(-1);
var tomorrow = now.AddDays(1);
var nextMonth = now.AddMonths(1);
var nextYear = now.AddYears(1);

Console.WriteLine($"now = {now}");
Console.WriteLine($"yesterday = {yesterday}");
Console.WriteLine($"tomorrow = {tomorrow}");
Console.WriteLine($"nextMonth = {nextMonth}");
Console.WriteLine($"nextYear = {nextYear}");