probleme recursive 21.09.2015

#include <iostream>

using namespace std;
int factorial (int n )
{
    if(n==0)
    return 1;
    else
        return factorial(n-1)*n;
}
 void factorial (int n ,int &f)
 {
     if(n==0)
        f=1;
     else
      {

  factorial (n-1,f);
     f=f*n;      }
 }

int cmmdc(int a ,int b)
  {
      if(b==0)
        return a;
        else
            return cmmdc(b,a%b);

  }

   int sumcif(int x)
   {
       if(x==0)
        return 0;
       else
        return x%10+sumcif(x/10);
   }
    void sumcif(int n,int &s)
    {
        if(n==0)
            s=0;
        else
           {

           sumcif(n/10,s);
        s=s+n%10;
        }
    }

int nr_cif_zero(int x)

{
        if(x>9)
        {
        if(x%10==0)
        return 1+nr_cif_zero(x/10);
    else
        return nr_cif_zero(x/10);
        }
        else
            if(x!=0)
            return 0;
        else
            return 1;

}