UMER’S Algorithmfor date to day conversion
Suppose we have a date D-M-Y and we want to determine the day of week on which that date falls. We can do this in three simple steps:
IMPORTANT TERM: Before starting we have to learn an important term, the mod operator. The mod operator returns the remainder after division of two numbers. For example, (13 mod 5) = 3 because when we divide 13 by 5, the remainder is 3.
Step 1:
The first step is to determine the values of some important terms:
1. Y = The year found from the date. For example, in 14th August 1947, Y=1947.
2. D = Date of the month. For example, in 14th August 1947, D= 14.
3. L.Y = (Y – (Y mod 4) ) ÷ 4
4. M.C = It is found according to the month from the table below:
Month | M.C |
January | 0 |
February | 3 |
March | 3 |
April | 6 |
May | 1 |
June | 4 |
July | 6 |
August | 2 |
September | 5 |
October | 0 |
November | 3 |
December | 5 |
5. n and c are Boolean variables (Their value is either 0 or 1)
· n = 1 if (Y mod 4) = 0 , otherwise n = 0.
· c = 1 if the month is January or February otherwise c= 0.
Step 2:
The second step is to compute the DayCodeusing a formula:
DayCode =(5+Y +D +L.Y+ M.C–nc)mod 7
DayCode =(5+Y +D +L.Y
Step 3:
The final step is to determine the Day using DayCode from the table below:
DayCode | Day |
0 | Sunday |
1 | Monday |
2 | Tuesday |
3 | Wednesday |
4 | Thursday |
5 | Friday |
6 | Saturday |
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