факториал в С++

unsigned long fact(int x) {
    if (x == 0) return 1;
    return x * fact(x - 1);
}

#include <iostream>
 
 
long Factorial (int n)
{
    if (n==0) return 1;
    else return Factorial(n-1)*n;
}
 
int main()
{
    int n;
    std:: cin >> n;
    std:: cout << Factorial(n) << "\n";
    system ("pause");
    return 0;
}

#include <iostream>
using namespace std;
 
unsigned long fact(unsigned long val)
{
    unsigned long ret = val;
    if(0 < (val = val - 1))
        ret *= fact(val);
    return ret;
}
 
int main()
{
    unsigned long num;
    while(true)
    {
        cout<<"Enter num  : ";
        cin>>num;
        cout<<"Recurs fact: "<<fact(num)<<endl;
    }
    return 0;
}

unsigned long fact(unsigned long val)
{
        unsigned long ret = val ? val : 1;
        if(0 < val && 0 < (val = val - 1))
                ret *= fact(val);
        return ret;
}

unsigned long fact(unsigned long n)
{
   return n ? n * fact(n - 1) : 1;
}