求解，因为是新手最好带点注释谢谢 - 黑马程序员技术交流社区

class Program
{
static void Main(string[] args)
{
Console.WriteLine(" |----------------------------------------------------------------|");
Console.WriteLine(" | 这是一个“输入一个日期，求该日期是这一年中的第几天 ”的程序 |");
Console.WriteLine(" |----------------------------------------------------------------|");
Console.WriteLine();
Console.WriteLine("您需要输入一个日期...");
Console.WriteLine();
Console.Write("您需要输入年份：");
int year = int.Parse(Console.ReadLine());
Console.WriteLine();
Console.Write("您需要输入月份：");
int month = int.Parse(Console.ReadLine());
Console.WriteLine();
Console.Write("您需要输入具体日期（几号？）：");
int date = int.Parse(Console.ReadLine());
Console.WriteLine();
Console.Write("{0}年{1}月{2}日是一年中的第", year, month, date);
bool b = Leap_Common_year(year);//判断平年还是闰年
switch (month) //判断月份
{
case 1: month_1(date); break;//根据日期计算出是哪一天
case 2: month_2(date); break;
case 3: month_3(date, b); break;
case 4: month_4(date, b); break;
case 5: month_5(date, b); break;
case 6: month_6(date, b); break;
case 7: month_7(date, b); break;
case 8: month_8(date, b); break;
case 9: month_9(date, b); break;
case 10: month_10(date, b); break;
case 11: month_11(date, b); break;
case 12: month_12(date, b); break;
default: Console.WriteLine("您输入的月份有误..."); break;
}
Console.ReadKey();
}
static bool Leap_Common_year(int year)//判断平年还是闰年
{
bool b;
if (year % 4 == 0 && year % 100 != 0)
{
b = false;
}
else
{
b = true;
}
return b;
}
static void month_1(int date)
{
Console.Write("{0}天。", date);
}
static void month_2(int date)
{
int d;
d = 31 + date;
Console.Write("{0}天", d);
}
static void month_3(int date, bool b)
{
int d;
if (b)
{
d = 31 + 28 + date;
}
else
{
d = 31 + 29 + date;
}
Console.Write("{0}天", d);
}
static void month_4(int date, bool b)
{
int d;
if (b)
{
d = 31 + 28 + 31 + date;
}
else
{
d = 31 + 29 + 31 + date;
}
Console.Write("{0}天", d);
}
static void month_5(int date, bool b)
{
int d;
if (b)
{
d = 31 + 28 + 31 + 30 + date;
}
else
{
d = 31 + 29 + 31 + 30 + date;
}
Console.Write("{0}天", d);
}
static void month_6(int date, bool b)
{
int d;
if (b)
{
d = 31 + 28 + 31 + 30 + 31 + date;
}
else
{
d = 31 + 29 + 31 + 30 + 31 + date;
}
Console.Write("{0}天", d);
}
static void month_7(int date, bool b)
{
int d;
if (b)
{
d = 31 + 28 + 31 + 30 + 31 + 30 + date;
}
else
{
d = 31 + 29 + 31 + 30 + 31 + 30 + date;
}
Console.Write("{0}天", d);
}
static void month_8(int date, bool b)
{
int d;
if (b)
{
d = 31 + 28 + 31 + 30 + 31 + 30 + 31 + date;
}
else
{
d = 31 + 29 + 31 + 30 + 31 + 30 + 31 + date;
}
Console.Write("{0}天", d);
}
static void month_9(int date, bool b)
{
int d;
if (b)
{
d = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + date;
}
else
{
d = 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + date;
}
Console.Write("{0}天", d);
}
static void month_10(int date, bool b)
{
int d;
if (b)
{
d = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + date;
}
else
{
d = 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + date;
}
Console.Write("{0}天", d);
}
static void month_11(int date, bool b)
{
int d;
if (b)
{
d = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + date;
}
else
{
d = 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + date;
}
Console.Write("{0}天", d);
}
static void month_12(int date, bool b)
{
int d;
if (b)
{
d = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + date;
}
else
{
d = 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + date;
}
Console.Write("{0}天", d);
}
}

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while (true)
{
string date;
int leapYear;
int year;
int month;
int day;
Console.WriteLine("请输入日期，格式为xxxx-aa-bb");
date = Console.ReadLine();
year = Convert.ToInt32(date.Substring(0, 4));
month = Convert.ToInt32(date.Substring(5, 2));
day = Convert.ToInt32(date.Substring(8, 2));
if ((year % 400 == 0) || (year % 4 == 0) && (year % 100 != 0))
{
leapYear = 1;
}
else
{
leapYear = 0;
}
int[] montharr = new int[] { 31, 28 + leapYear, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
bool checkDate = (day > montharr[month - 1]) || (day < 1) || (month > 12) || (month < 1);
if (!checkDate)
{
int dayOfYear = 0;
for (int i = 0; i < month - 1; i++)//获取当月之前的月份天数和
{
dayOfYear += montharr[i];
}
dayOfYear += day;//加上当前月的天数
Console.WriteLine(dayOfYear);
}
else
{
Console.WriteLine("输入的日期不在范围内");
}
Console.ReadKey();
}

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你这个是黑马的基础测试吧。本来不想写的但是看到大家写的代码过于繁琐，我就拿出来献一下丑（虽然现在只会写一些简单的控制台），事先说明，没有进行字符串的校验，同时也没有封装。

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int iweek;
string week;
//因为0001年01月01日为星期一，且0001年的星期数为 dayOfYear % 7 的结果，所以可得下列表达式
iweek = ((year - 1) * 365 + dayOfYear + (year - 1) / 400 - (year - 1) / 100 + (year - 1) / 4) % 7;
switch (iweek)
{
case 1:week="星期一";break;
case 2:week="星期二";break;
case 3:week="星期三";break;
case 4:week="星期四";break;
case 5:week="星期五";break;
case 6:week="星期六";break;
default:week ="星期日"; break;
}

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