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Add Zeller's Congruence Algorithm in Math #996

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Merged
merged 5 commits into from
Apr 27, 2022
Merged

Add Zeller's Congruence Algorithm in Math #996

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b955346
Create ZellersCongruenceAlgorithm.js
merelymyself Apr 25, 2022
525df1c
Create ZellersCongruenceAlgorithm.test.js
merelymyself Apr 25, 2022
d007557
toThrowError not valid?
merelymyself Apr 25, 2022
9dc30cd
Update ZellersCongruenceAlgorithm.test.js
merelymyself Apr 25, 2022
86c7eec
throw, not return.
merelymyself Apr 25, 2022
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26 changes: 26 additions & 0 deletions Maths/ZellersCongruenceAlgorithm.js
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Original file line number Diff line number Diff line change
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// Zeller's Congruence Algorithm finds the day of the week from the Gregorian Date. Wikipedia: https://en.wikipedia.org/wiki/Zeller%27s_congruence
export const zellersCongruenceAlgorithm = (day, month, year) => {
if (typeof day !== 'number' || typeof month !== 'number' || typeof year !== 'number') {
throw new TypeError('Arguments are not all numbers.')
}
const q = day
let m = month
let y = year
if (month < 3) {
m += 12
y -= 1
}
day =
(q + Math.floor(26 * (m + 1) / 10) + (y % 100) + Math.floor((y % 100) / 4) + Math.floor(Math.floor(y / 100) / 4) + (5 * Math.floor(y / 100))) %
7
const days = [
'Saturday',
'Sunday',
'Monday',
'Tuesday',
'Wednesday',
'Thursday',
'Friday'
]
return days[day]
}
17 changes: 17 additions & 0 deletions Maths/test/ZellersCongruenceAlgorithm.test.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,17 @@
import { zellersCongruenceAlgorithm } from '../ZellersCongruenceAlgorithm'

function testZeller (day, month, year, expected) {
test('Testing on ' + day + '/' + month + '/' + year, () => {
expect(zellersCongruenceAlgorithm(day, month, year)).toBe(expected)
})
}

test('Testing on this/should/throw', () => {
expect(() => {
zellersCongruenceAlgorithm('this', 'should', 'error')
}).toThrowError(new TypeError('Arguments are not all numbers.'))
})
testZeller(25, 1, 2013, 'Friday')
testZeller(26, 1, 2013, 'Saturday')
testZeller(16, 4, 2022, 'Saturday')
testZeller(25, 4, 2022, 'Monday')