factorial using recursion in c 2b 2b

1#include<bits/stdc++.h>
2#include<stdio.h>
3using namespace std;
4
5int fact(int i){
6	if (i <= 1) return 1;
7  	else return i*fact(i-1);
8}
9
10int main(){
11  	ios::sync_with_stdio(0);
12  	cin.tie(0);
13  	int N;
14  	cin >> N;
15  	cout << fact(N) << "\n";
16  	return 0;
17}

1#include <iostream>
2using namespace std;
3
4int factorial(int n)
5{
6    if (n < 0)
7        return (-1); /*Wrong value*/
8    if (n == 0)
9        return (1); /*Wrong value*/
10    else
11    {
12      return (n * factorial(n - 1));
13    }
14}
15
16int main()
17{
18    int number, ans;
19    cin >> number;
20    ans = factorial(number);
21    cout << ans;
22    return 0;
23}
24

1#include <cmath>
2
3int fact(int n){
4    return std::tgamma(n + 1);  
5}    
6// for n = 5 -> 5 * 4 * 3 * 2 = 120 
7//tgamma performas factorial with n - 1 -> hence we use n + 1

1#include <iostream> 
2
3//n! = n(n-1)!
4int factorial (int n)
5{
6  if (n ==0)
7  {
8    return 1; 
9  }
10  else 
11  {
12	return n * factorial(n-1); 
13  }
14}