我需要使用 c# 从 2015 年减去一年（比方说 1991 年）

Question

几个小时以来，我一直在寻找解决这个非常简单的代码的方法。我昨天开始了我的编程生涯，今天得到了 Visual Studio。我曾尝试玩 "Hello World" 练习，但是从彼此中扣除两年变得比我想象的要困难。

我的代码确实显示了我目前的水平，我求求你们，我到底做错了什么？

using System;

namespace HelloWorld
{
    class Hello
    {
        static void Main()
        {
            Console.WriteLine("Hello World!");
            // Keep the console window open in debug mode.

            Console.Write("Please enter your first name: ");
            string firstName = Console.ReadLine();

            Console.Write("Please enter your last name: ");
            string lastName = Console.ReadLine();
            Console.WriteLine("");

            Console.WriteLine("You're Name is: " + firstName + " " + lastName);

            Console.WriteLine("");
            Console.WriteLine("Please enter your birthyear");

            Console.WriteLine("");
            string yob = Console.ReadLine();

            Console.WriteLine("");

            Console.WriteLine("Today it's...");

            DateTime time = DateTime.Now;   // Use current time.    
            string format = "yyyy";   // Use this format. (MMM ddd d HH:mm yyyy)
            Console.WriteLine(time.ToString(format)); // Write to console.
            Console.WriteLine(" ");
            Console.WriteLine("Which means that you are approximately....");

            Console.WriteLine("?? Years old");

            //timespan between `datenow` and `date1`

            Console.ReadKey();
        }
    }
}

Answer 1

System.TimeSpan 将帮助您计算差异。快速搜索 "difference in dates c#" 得到了这段代码。如果您想了解更多信息，页面上有多种方法。如果您需要更多帮助，请告诉我。

using System;
using System.Collections.Generic;
using System.Text;

namespace Console_DateTime
{
    class Program
    {
        static void Main(string[] args)
        {
            System.DateTime dtTodayNoon = new System.DateTime(2006, 9, 13, 12, 0, 0);
            System.DateTime dtTodayMidnight = new System.DateTime(2006, 9, 13, 0, 0, 0);
            System.TimeSpan diffResult = dtTodayNoon.Subtract(dtYestMidnight);
            Console.WriteLine("Yesterday Midnight - Today Noon = " + diffResult.Days);
            Console.WriteLine("Yesterday Midnight - Today Noon = " + diffResult.TotalDays);
            Console.ReadLine();
        }
    }
}

来源：c-sharpcorner.com

编辑：忘记解释的第一行。

Answer 2

将yob转换为整数：

int yearOfBirth = int.Parse(yob); //This could fail! See note below

然后从今天的年份中减去：

int yearsOld = DateTime.Now.Year - yearOfBirth;
Console.WriteLine(yearsOld + " years old");

注意：如果您输入的不是数字，例如 two thousand，int.Parse 命令可能会失败。查看 int.TryParse 来处理这种情况。

Answer 3

    // get current time
    DateTime now = DateTime.Now;

    // get year of birth from user
    String myYear = Console.ReadLine();

    // construct a DateTime from that year
    DateTime my = new DateTime(Convert.ToInt16(myYear), 1, 1);

    // devide by 365 and convert to int
    Console.Write(Convert.ToInt16((now - my).TotalDays) / 365);

我需要使用 c# 从 2015 年减去一年（比方说 1991 年）

I need to deduct a year (lets say 1991) from 2015, using c#

c#

timespan