subprograme recursive

int factorial(int n)
{ if(n == 0) return 1; return factorial(n-1)*n;
}

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

int scif(int a)
{ if(a == 0) return 0; return scif(a/10) + a%10;
}