/*
 * Testing Collatz conjecture ...
 */

#include <stdio.h>
#include <time.h>
#include <limits.h>

#define MAX (LONG_MAX/3 - 1)

long stopcntr = 0L;

void collatz_init(void)
{
    stopcntr = 0L;
}

long collatz(long n)
{
   if(n == 1)
   {
       return stopcntr;
   }
   else if (n >= MAX)
   {
       return -1L;
   }
   else
   {
       if (n%2 == 0)
       {
            n /= 2;
       }
       else
       {
            n = 3*n + 1;
       }
       printf("%ld\n", n); 
       collatz(n);
       stopcntr++;
   }
}

int main(void)
{
    clock_t begin, end;
    double time_spent;
    begin = clock();

    collatz_init();
    long n = 12346L;
    long i = collatz(n);
    printf("%ld     %ld\n", n, i); 

    end = clock();
    time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
    printf("%f sec\n", time_spent); 

    return 0;
}