// ---------------------------------------
//   recurse.cpp  record recursion depth
// ---------------------------------------
 #include "w.h"

 long fact(int n, int &d) // d counts calls to fact
  { if (n == 1) return 1;
	 else { d++; return n*fact(n-1,d); }}

 long fib(int n, int &d) // calls to fib
 { if ((n ==1)||(n == 2)) return 1;
	else { d++; return fib(n-2,d)+fib(n-1,d); }}


 //----------------------------------------------------
 void main()
  {

	 int k,d;
	 nl(0);
	 banner("recurse.cpp");
	 k = 9;
	 d = 0;
	 p("fact(");p(k); pl(") = ",fact(k,d));
    pl("recursion depth = ",d);
	 nl();

	 // default int arithmetic 'stops' at 2^15-1

	 p("1*2*3*4*5*6*7*8*9 = "); cout << 1*2*3*4*5*6*7*8*9; nl();
	 long g = 1; // store the result in long
    for (int i = 2; i < 10; i++) g = g*i;
	 pl(g);
	 nl();


	 k = 20;
    d = 0;
    p("fib(");p(k); pl(") = ",fib(k,d));
	 pl("calls to fib = ",d);
	 


}
/* output
   -------------
    recurse.cpp
   -------------
   fact(9) = 362880
   recursion depth = 8

   1*2*3*4*5*6*7*8*9 = -30336
   362880

   fib(20) = 6765
   calls to fib = 6764



*/
/* ------------------------------------------------
Note  The Tower of Hanoi
This famous puzzle is solved by one recursive function.
Can you fill in the details?

void hanoi::movetower(int j, int a, int b)
{ if (j > 0) 
	{ 
	  movetower(j-1, a, otherpeg(a,b));
	  movedisc(j,a,b);
	  movetower(j-1,otherpeg(a,b),b);
	}
}

--------------------------------------------------*/