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Binomial coefficient implementation (#1094)

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	`1`	`+/*`
	`2`	`+ * Author: Akshay Dubey (https://github.com/itsAkshayDubey)`
	`3`	`+ * Binomial Coefficient: https://en.wikipedia.org/wiki/Binomial_coefficient`
	`4`	`+ * function to find binomial coefficient of numbers n and k.`
	`5`	`+ * return binomial coefficient of n,k`
	`6`	`+ */`
	`7`	`+`
	`8`	`+/**`
	`9`	`+ * @function findBinomialCoefficient`
	`10`	`+ * @description -> this function returns bonimial coefficient`
	`11`	`+ * of two numbers n & k given by n!/((n-k)!k!)`
	`12`	`+ * @param {number} n`
	`13`	`+ * @param {number} k`
	`14`	`+ * @returns {number}`
	`15`	`+ */`
	`16`	`+`
	`17`	`+import { calcFactorial } from './Factorial'`
	`18`	`+`
	`19`	`+export const findBinomialCoefficient = (n, k) => {`
	`20`	`+ if ((typeof n !== 'number') \|\| (typeof k !== 'number')) {`
	`21`	`+ throw Error('Type of arguments must be number.')`
	`22`	`+ }`
	`23`	`+ if (n < 0 \|\| k < 0) {`
	`24`	`+ throw Error('Arguments must be greater than zero.')`
	`25`	`+ }`
	`26`	`+ let product = 1`
	`27`	`+ for (let i = n; i > k; i--) {`
	`28`	`+ product *= i`
	`29`	`+ }`
	`30`	`+ return product / calcFactorial(n - k)`
	`31`	`+}`

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	`1`	`+import { findBinomialCoefficient } from '../BinomialCoefficient.js'`
	`2`	`+`
	`3`	`+describe('Testing findBinomialCoefficient function', () => {`
	`4`	`+ it('should return 56', () => {`
	`5`	`+ const binomialCoefficient = findBinomialCoefficient(8, 3)`
	`6`	`+ expect(binomialCoefficient).toBe(56)`
	`7`	`+ })`
	`8`	`+`
	`9`	`+ it('should return 10', () => {`
	`10`	`+ const binomialCoefficient = findBinomialCoefficient(5, 2)`
	`11`	`+ expect(binomialCoefficient).toBe(10)`
	`12`	`+ })`
	`13`	`+`
	`14`	`+ it('should throw error when supplied arguments other than number', () => {`
	`15`	`+ expect(() => { findBinomialCoefficient('eight', 'three') }).toThrow(Error)`
	`16`	`+ })`
	`17`	`+`
	`18`	`+ it('should throw error when n is less than zero', () => {`
	`19`	`+ expect(() => { findBinomialCoefficient(-1, 3) }).toThrow(Error)`
	`20`	`+ })`
	`21`	`+`
	`22`	`+ it('should throw error when k is less than zero', () => {`
	`23`	`+ expect(() => { findBinomialCoefficient(1, -3) }).toThrow(Error)`
	`24`	`+ })`
	`25`	`+`
	`26`	`+ it('should throw error when n and k are less than zero', () => {`
	`27`	`+ expect(() => { findBinomialCoefficient(-1, -3) }).toThrow(Error)`
	`28`	`+ })`
	`29`	`+})`

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