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  4. Calculate How Many Mondays in a Particular Month

Calculate How Many Mondays in a Particular Month

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  • N Nagy Vilmos

    NSS


    Panic, Chaos, Destruction. My work here is done.

    P Offline
    P Offline
    PIEBALDconsult
    wrote on last edited by
    #12

    Not everyone picks up on these things.

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    • L Lost User

      I'm not too sure about the various constants, but it looks like The Right Way to do it

      M Offline
      M Offline
      musefan
      wrote on last edited by
      #13

      On second thoughts, it does not look much improved :laugh: The constants are OK, they will never need to change

      Life goes very fast. Tomorrow, today is already yesterday.

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      • M musefan

        Here's a method you could use...

        int CountDaysInMonth(int month, int year, DayOfWeek dayToCount)
        {
        DateTime dt = new DateTime(year, month, 1);
        int result = 0;
        for(int i = 0; i < DateTime.DaysInMonth(year, month); i++)
        {
        if(dt.DayOfWeek == dayToCount)
        result++;
        dt.AddDays(1);
        }
        return result;
        }

        Life goes very fast. Tomorrow, today is already yesterday.

        M Offline
        M Offline
        musefan
        wrote on last edited by
        #14

        What??? It does not work? What's with the 'Bad Answer' again?

        Life goes very fast. Tomorrow, today is already yesterday.

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        • C cdpace

          Hello guys Can you please help me with this one? I want to make a mehtod that when you pass it a particular month and year it will return you the ammount of Mondays that are found in that Month of that particular day. Anyone has any ideas? Thank you in adavance Regards, Christian Pace

          L Offline
          L Offline
          Luc Pattyn
          wrote on last edited by
          #15

          Obviously you do not need any loop or conditional for this. Have a look at:

          int mondays=(DateTime.DaysInMonth(year, month) + (int)new DateTime(year, month, 6).DayOfWeek) / 7;

          What remains of this homework is for you to figure out why the expression is what it is! :)

          Luc Pattyn [Forum Guidelines] [My Articles]


          I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages


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          • L Lost User

            I'm not too sure about the various constants, but it looks like The Right Way to do it

            L Offline
            L Offline
            Luc Pattyn
            wrote on last edited by
            #16

            harold aptroot wrote:

            it looks like The Right Way to do it

            really? :)

            Luc Pattyn [Forum Guidelines] [My Articles]


            I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages


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            • L Luc Pattyn

              harold aptroot wrote:

              it looks like The Right Way to do it

              really? :)

              Luc Pattyn [Forum Guidelines] [My Articles]


              I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages


              L Offline
              L Offline
              Lost User
              wrote on last edited by
              #17

              *reconsiders* Yes? No seriously, no matter how wrong it was, not having a loop made it much closer than all those other entries..

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              • L Luc Pattyn

                Obviously you do not need any loop or conditional for this. Have a look at:

                int mondays=(DateTime.DaysInMonth(year, month) + (int)new DateTime(year, month, 6).DayOfWeek) / 7;

                What remains of this homework is for you to figure out why the expression is what it is! :)

                Luc Pattyn [Forum Guidelines] [My Articles]


                I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages


                P Offline
                P Offline
                PIEBALDconsult
                wrote on last edited by
                #18

                No, it's obvious that no loop is required, but I still have two conditionals in mine. I, like some of the others, am not content to hard code Monday, but would prefer to take the day of the week as a parameter. I haven't tried yours yet, but I don't see how it can be a general solution for any specified day of the week. On the whole, I expect the OP's teacher only wants to prove that he's smarter than his students.

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                • P PIEBALDconsult

                  No, it's obvious that no loop is required, but I still have two conditionals in mine. I, like some of the others, am not content to hard code Monday, but would prefer to take the day of the week as a parameter. I haven't tried yours yet, but I don't see how it can be a general solution for any specified day of the week. On the whole, I expect the OP's teacher only wants to prove that he's smarter than his students.

                  L Offline
                  L Offline
                  Luc Pattyn
                  wrote on last edited by
                  #19

                  IMO it works for all years and months, I checked for this year only. With a day-of-week parameter it becomes:

                  int Xdays=(DateTime.DaysInMonth(year, month) + (int)new DateTime(year, month, 7-dayOfWeek).DayOfWeek) / 7;

                  where dayOfWeek is 0=SU, 1=MO, ... 6=SA [ADDED] so you can also use (int)DayOfWeek [/ADDED] :)

                  Luc Pattyn [Forum Guidelines] [My Articles]


                  I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages


                  modified on Wednesday, November 18, 2009 3:36 PM

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                  • P PIEBALDconsult

                    No, it's obvious that no loop is required, but I still have two conditionals in mine. I, like some of the others, am not content to hard code Monday, but would prefer to take the day of the week as a parameter. I haven't tried yours yet, but I don't see how it can be a general solution for any specified day of the week. On the whole, I expect the OP's teacher only wants to prove that he's smarter than his students.

                    L Offline
                    L Offline
                    Luc Pattyn
                    wrote on last edited by
                    #20

                    PIEBALDconsult wrote:

                    I expect the OP's teacher only wants to prove that he's smarter than his students

                    The teacher may be shaded then by a cheating student. :laugh:

                    Luc Pattyn [Forum Guidelines] [My Articles]


                    I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages


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                    • M musefan

                      Improved...

                      int CountDaysInMonth(int month, int year, DayOfWeek dayToCount)
                      {
                      DateTime dt = new DateTime(year, month, 1);
                      int firstInstance = 1;
                      if((int)dt.DayOfWeek > (int)dayToCount)
                      firstInstance += (7 - (int)dt.DayOfWeek) + (int)dayToCount;
                      else if((int)dt.DayOfWeek < (int)dayToCount)
                      firstInstance += (int)dayToCount - (int)dt.DayOfWeek;
                      return firstInstance <= (DateTime.DaysInMonth(month, year) - 28) ? 5 : 4;
                      }

                      ...I think the logic is right. [EDIT] That was way off, I fixed now... I think!

                      Life goes very fast. Tomorrow, today is already yesterday.

                      P Offline
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                      PIEBALDconsult
                      wrote on last edited by
                      #21

                      What I came up with is similar to that:

                      public static int
                      F
                      (
                      int Year
                      ,
                      int Month
                      ,
                      System.DayOfWeek DayOfWeek
                      )
                      {
                      int d = (int) DayOfWeek - (int) (new System.DateTime ( Year , Month , 1 )).DayOfWeek ;

                      if ( d < 0 )
                      {
                          d += 7 ;
                      }
                      
                      int n = System.DateTime.DaysInMonth ( Year , Month ) - 28 ;
                      
                      return ( d < n ? 5 : 4 ) ;
                      

                      }

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                      • L Luc Pattyn

                        PIEBALDconsult wrote:

                        I expect the OP's teacher only wants to prove that he's smarter than his students

                        The teacher may be shaded then by a cheating student. :laugh:

                        Luc Pattyn [Forum Guidelines] [My Articles]


                        I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages


                        C Offline
                        C Offline
                        cdpace
                        wrote on last edited by
                        #22

                        Lol guys Thank you very much for the help ;) but actually this ain't for homework hehe, this is part of a payroll system that I am developing at work and with the deadline stress and from being tired because been programming 8 hours strait i couldn't find a solution for this so i turned to some help ;) hehe thank you again guys.

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