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e112434dee
* Add prettier config * test: add test to check for absolute function * chore: es5 to es6 * test: add test to check mean function * test: add test for sum of digit * test: add test for factorial * test: add test for fibonnaci * test: add test for find HCF * test: add test for lcm * test: add gridget test * test: add test for mean square error * test: add test for modular binary exponentiation * test: add tests for palindrome * test: add test for pascals triangle * test: add tests for polynomial * test: add tests for prime check * test: add tests for reverse polish notation * test: add tests for sieve of eratosthenes * test: add tests for pi estimation monte carlo method * chore: move tests to test folder * chore: fix standardjs errors
51 lines
1.1 KiB
JavaScript
51 lines
1.1 KiB
JavaScript
/*
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author: PatOnTheBack
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license: GPL-3.0 or later
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Modified from:
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https://github.com/TheAlgorithms/Python/blob/master/maths/factorial_python.py
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This script will find the factorial of a number provided by the user.
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More about factorials:
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https://en.wikipedia.org/wiki/factorial
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*/
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'use strict'
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const calcRange = (num) => {
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// Generate a range of numbers from 1 to `num`.
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let i = 1
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const range = []
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while (i <= num) {
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range.push(i)
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i += 1
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}
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return range
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}
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const calcFactorial = (num) => {
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let factorial
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const range = calcRange(num)
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// Check if the number is negative, positive, null, undefined, or zero
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if (num < 0) {
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return 'Sorry, factorial does not exist for negative numbers.'
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}
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if (num === null || num === undefined) {
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return 'Sorry, factorial does not exist for null or undefined numbers.'
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}
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if (num === 0) {
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return 'The factorial of 0 is 1.'
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}
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if (num > 0) {
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factorial = 1
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range.forEach(function (i) {
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factorial = factorial * i
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})
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return `The factorial of ${num} is ${factorial}`
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}
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}
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export { calcFactorial }
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