UMER’S Algorithm
for 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:
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.
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.
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.
month. For example, in 14th August 1947, D
= 14.
3. L.Y = (Y – (Y mod 4) )
÷ 4
÷ 4
4. M.C = It is found
according to the month from the table below:
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 and
c are Boolean variables (Their value is
either 0 or 1)
·
n = 1
if (Y mod 4) = 0 , otherwise n = 0.
n = 1
if (Y mod 4) = 0 , otherwise n = 0.
·
c = 1
if the month is January or February otherwise c
= 0.
c = 1
if the month is January or February otherwise c
= 0.
Step 2:
The second step is to compute the DayCode
using a formula:
DayCode
=(5+Y +D +L.Y +M.C–nc)mod 7
using a formula:
DayCode
=(5+Y +D +L.Y +M.C–nc)mod 7
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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