diff --git a/Maths/AliquotSum.js b/Maths/AliquotSum.js new file mode 100644 index 000000000..5f61d87c5 --- /dev/null +++ b/Maths/AliquotSum.js @@ -0,0 +1,32 @@ +/* + A program to calculate the Aliquot Sum of a number. + The aliquot sum of a number n, is the sum of all the proper divisors of n apart from n itself + For example, for the number 6 + The divisors are 1, 2, 3 (we don't consider 6), so its aliquot sum is 1 + 2 + 3 = 6 + 1 is the only number whose aliquot sum is 0 (since its only divisor is 1 and aliquot sum of a number couldn't have itself) + For all prime numbers, the aliquot sum is 1, since their only divisor apart from themselves is 1 + Article on Aliquot Sum: https://en.wikipedia.org/wiki/Aliquot_sum + */ + +/** + * @param {Number} input The number whose aliquot sum you want to calculate + */ +function aliquotSum (input) { + // input can't be negative + if (input < 0) throw new TypeError('Input cannot be Negative') + + // input can't be a decimal + if (Math.floor(input) !== input) throw new TypeError('Input cannot be a Decimal') + + // Dealing with 1, which isn't a prime + if (input === 1) return 0 + + let sum = 0 + for (let i = 1; i <= (input / 2); i++) { + if (input % i === 0) sum += i + } + + return sum +} + +export { aliquotSum } diff --git a/Maths/test/AliquotSum.test.js b/Maths/test/AliquotSum.test.js new file mode 100644 index 000000000..88a64299d --- /dev/null +++ b/Maths/test/AliquotSum.test.js @@ -0,0 +1,15 @@ +import { aliquotSum } from '../AliquotSum' + +describe('Aliquot Sum of a Number', () => { + it('Aliquot Sum of 6', () => { + expect(aliquotSum(6)).toBe(6) + }) + + it('Aliquot Sum of 1', () => { + expect(aliquotSum(1)).toBe(0) + }) + + it('Aliquot Sum of 28', () => { + expect(aliquotSum(28)).toBe(28) + }) +})