Thread: Recursion

I have a simple recursion program that I copied out of a book. It works fine, but I'm still having trouble understanding exactly what goes on during recursion. I tried inserting printf statements in my code to see what was going on, but it only confused me more... :-(

Code:

#include <stdio.h>

long double factr (long double n);

void main ()
{
     long double highest;

     do
     {
           printf ("\n\nType '0' to quit.");
           printf ("\n\nPlease specify a max range to calculate factorials.\n");
           scanf ("%Lf", &highest);

           if (highest > 0)
           {
                  factr (highest);
           }
     } while (highest > 0);

     printf("\n\n");
     highest = 0;
}

long double factr (long double n)
{
     long double answer;

     printf ("Start Recursion!  %d   %d\n", n, answer);
     if (n == 1) return (1);
     answer = n * factr (n-1);  //recursive call
     printf ("\n%g   %g", n, answer);
     return (answer);
}

What I don't understand is why the "Start Recursion!" prints before any calculations are made & how it's able to print out the correct answers!?

mw