解説を視る前に書いたコード(エラーになるが原因は分かっていない)
class Program
{
static int[] NextDay(int year,int month, int day)
{
day++;
if(day > LastDay(year, month))
{
day = 1;
month++;
}
if(month > 12)
{
month = 1;
year++;
}
return new int[] { year, month, day };
}
//１８００年１月１日からの日数を計算するメソッド
static int CountDay (int year,int month,int day)
{
int y = 1800, m = 1, d = 1;
int count = 0;
//400年分の日数
int daysOf400years = 365 * 400 + (400 / 4) - (400 / 100) + (400 + 400);
//400年の倍数飛ぶ
count += ((year - 1800) / 400) * daysOf400years;
y = year - (year - 1800) % 400;
while(!(y == year && m == month && d == day))
{
count++;
int[] nextDay = NextDay(y, m, d);
y = nextDay[0];
m = nextDay[1];
d = nextDay[2];
}
return count;
}
static int LastDay(int year, int month)
{
switch (month)
{
case 2:
if(year % 400 == 0 || (year % 100 != 0 && year % 4 == 0))
{
return 29;
}
else
{
return 28;
}
case 4:
case 6:
case 9:
case 11:
return 30;
default:
return 31;
}
}
static int WhatDay(int year, int month, int day)
{
int dayOfweek = 3; //1800年１月１日は水曜日
int count = CountDay(year, month, day);
return (dayOfweek + count) % 7;
}
static void Main(string[] args)
{
string[] input = Console.ReadLine().Trim().Split(' ');
int y = int.Parse(input[0]);
int m = int.Parse(input[1]);
//y年m月1日の曜日を求める
int dayOfWeek = WhatDay(y, m,1);
//日→０、月→1、・・・・ 土→6
//y年m月は何日か
int lastDay = LastDay(y, m);
for(int i = 0; i < dayOfWeek; i++)
{
Console.Write(" ");
}
for(int i = 1; i < 10; i++)
{
Console.Write(" {0}", i);
//日から金なら後ろに半角スペース、土なら改行
if(dayOfWeek != 6)
{
Console.Write(" ");
}
else
{
Console.WriteLine();
}
dayOfWeek = (dayOfWeek + 1) % 7;
}
for(int i = 10;i < lastDay+1; i++)
{
Console.Write("{0}", i);
//日から金なら後ろに半角スペース、土なら改行
if (dayOfWeek != 6)
{
Console.Write(" ");
}
else
{
Console.WriteLine();
}
dayOfWeek = (dayOfWeek + 1) % 7;
}
for(int i = dayOfWeek; i < 7; i++)
{
Console.Write(" ");
if (i != 6)
{
Console.Write(" ");
}
else
{
Console.WriteLine();
}
}
}
}
YouTubeの解説動画を視て書いたもの
メモ string.Formatメソッドで桁数を指定する方法[
string.Format("値は{0,5}です。", 10);
string.Format("値は{0,-5}です。", "ABC");
{}の中の変数を指定する番号の後に、カンマで区切って指定する。
プラスで右寄せ、マイナスで左寄せ。
class Program
{
static int[] NextDay(int year, int month, int day)
{
day++;
if (day > LastDay(year, month))
{
day = 1;
month++;
}
if (month > 12)
{
month = 1;
year++;
}
return new int[] { year, month, day };
}
static int LastDay(int year, int month)
{
switch (month)
{
case 2:
if (year % 400 == 0 || (year % 100 != 0 && year % 4 == 0))
{
return 29;
}
else
{
return 28;
}
case 4:
case 6:
case 9:
case 11:
return 30;
default:
return 31;
}
}
static int DayOfWeek(int year, int month, int day)
{
int y = 1800, m = 1, d = 1, dow = 3;
while(!(y == year && m == month && d == day))
{
int[] date = NextDay(y, m, d);
y = date[0];
m = date[1];
d = date[2];
dow = (dow + 1) % 7;
}
return dow;
}
static void Main(string[] args)
{
string[] input = Console.ReadLine().Trim().Split(' ');
int y = int.Parse(input[0]);
int m = int.Parse(input[1]);
string[][] cal = new string[6][];
for(int i = 0; i < 6; i++)
{
cal[i] = new string[7];
for(int j = 0; j < 7; j++)
{
cal[i][j] = " ";
}
}
//calを更新する
int line = 0, column = DayOfWeek(y, m, 1);
int day = 1;
while(day <= LastDay(y, m))
{
cal[line][column] = string.Format("{0,2}", day); //プラスで右寄せ、マイナスで左寄せ
day++;
line += (column + 1) / 7;
column = (column + 1) % 7;
}
DisplayCalendar(cal);
}
static void DisplayCalendar(string[][] cal)
{
for(int i = 0;i < cal.Length;i++)
{
Console.Write(cal[i][0]);
for(int j = 1; j < cal[i].Length; j++)
{
Console.Write(" {0}", cal[i][j]);
}
Console.WriteLine();
}
}
}