Weekday determination

I wnat determination the weekday whne I enter year ,month,and day. how should I do ? I try it

-----------------------------------------------------
year=input('enter year')
month=input('enter month')
day=input('enter day')

switch year
    case (1700:1799)
        y=4
    case (1800:1899)
        y=2
    case (1900:1999)
        y=0
    case (2000:2099)
        y=6
    case (2100:2299)
        y=2
    case (2300:2399)
        y=0
    case (2400:2499)
        y=6
    case (2500:2599)
        y=4
    case (2600:2699)
        y=2
end
x=mod(year,100)
x1=floor(x,4)
    switch month
        case 1
            m=0
        case 2
            m=3
        case 3
            m=3
        case 4
            m=6
        case 5
            m=1
        case 6
            m=4
        case 7
            m=6
        case 8
            m=2
        case 9
            m=5
        case 10
            m=0
        case 11
            m=3
        case 12
            m=5
    end

       d=mod((y+x1+m+day),7)
      switch d
          case 0
              s=Sunday
          case 1
              s=Monday
          case 2
              s=Tuesday
          case 3
              s=Wednesday
          case 4
              s=Thursday
          case 5 
             s=Friday
          case 6
              s=Saturday
      end
   fprintf('%g',s)
  ----------------------------------------------------------

Answer 1

[the cyclist]

Did you think of trying MATLAB's own the weekday() function?

[Jan]

Beside the fact that using toolbox function is efficient and stable, the algorithm in WEEKDAY is smart:

d = mod(fix(datenum(year, month, day)) - 2, 7) + 1

Answer 2

[Fangjun Jiang]

datestr(datenum(2011,12,8),'ddd')

Answer 3

[Andrei Bobrov]

function [dd,ddd] = dayweekwiki(y,m,d)

dd = rem( ceil( d + 497 * (m / 4800 + y / 400) + 16870921 / 2400 ) - 1 , 7) + 1;

if nargout > 1

      ds =   {'Monday'
              'Tuesday'
              'Wednesday'
              'Thursday'
              'Friday'
              'Saturday'
              'Sunday'};

      ddd = ds(dd);
end

[Jan]

Do you have a reference for this method?

[Andrei Bobrov]

Hi Jan! Only in russian language:

http://ru.wikibooks.org/wiki/%D0%90%D0%BB%D0%B3%D0%BE%D1%80%D0%B8%D1%82%D0%BC_%D0%B2%D1%8B%D1%87%D0%B8%D1%81%D0%BB%D0%B5%D0%BD%D0%B8%D1%8F_%D0%B4%D0%BD%D1%8F_%D0%BD%D0%B5%D0%B4%D0%B5%D0%BB%D0%B8

[Jan]

Thanks, Andrei. I think, I know what "ОСТАТОК 7" means. It reminds me to the "Omega 13".

[Andrei Bobrov]

this is "mod 7"

Answer 4

[Jan]

Another approach:

function dd = mmm(y,m,d)
t = [0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4];
y = y - (m < 3);
dd = mod(y + floor(y/4) - floor(y/100) + floor(y/400) + t(m) + d, 7) + 1;

See: Sakamoto's Method

About your original code:

switch year
  case (1700:1799)

This is no valid Matlab syntax. Better use

if 1700 <= year && year <1800
  ...
elseif year < 1900
  ...