1.6 KiB
1.6 KiB
title | id | challengeType |
---|---|---|
Factorial | 597b2b2a2702b44414742771 | 5 |
Description
Write a function to return the factorial of a number.
Factorial of a number is given by :
n! = n * (n-1) * (n-2) * ..... * 1For example : 3! = 3*2*1 = 6 4! = 4*3*2*1 = 24
Note : 0! = 1
Instructions
Tests
tests:
- text: <code>factorial</code> is a function.
testString: assert(typeof factorial === 'function', '<code>factorial</code> is a function.');
- text: <code>factorial(2)</code> should return a number.
testString: assert(typeof factorial(2) === 'number', '<code>factorial(2)</code> should return a number.');
- text: <code>factorial(3)</code> should return 6.")
testString: assert.equal(factorial(3),results[0],"<code>factorial(3)</code> should return 6.");
- text: <code>factorial(3)</code> should return 120.")
testString: assert.equal(factorial(5),results[1],"<code>factorial(3)</code> should return 120.");
- text: <code>factorial(3)</code> should return 3,628,800.")
testString: assert.equal(factorial(10),results[2],"<code>factorial(3)</code> should return 3,628,800.");
Challenge Seed
function factorial (n) {
// Good luck!
}
After Test
const results=[6,120,3628800];
Solution
function factorial(n) {
let sum = 1;
while (n > 1) {
sum *= n;
n--;
}
return sum;
}