calculate factorial

1int factorial(int n) {
2	int res = 1, i; 
3    for (i = 2; i <= n; i++) 
4        res *= i; 
5    return res; 
6}

1(apply * (range n 0 -1)) ; plug in anything for n for n factorial

1// METHOD ONE
2const factorialNumber = num => {
3    let factorials = []
4    for(let i = 1; i <= num; i++) factorials.push(i)
5    return factorials.reduce((acc , curr) => acc * curr, 1)
6}
7
8// METHOD TWO
9const factorialNumber = num => {
10    let factorial = 1, i = 1
11    while(i <= num){ factorial *= i; i++ }
12    return factorial
13}
14// METHOD THREE
15function factorialNumber(num) {
16    if(num < 1) return 1
17    else return factorialNumber(num - 1) * num
18}