#include <stdio.h>
#include <stdlib.h>

int  walk_recur( int dist );

main()
{
     int  distance,      /* how far to walk */
          count_walks;   /* how many ways to walk distance meters */

     printf( "\nHow far to walk?  " );
     scanf( "%d", &distance );
     if ( distance < 1 )      /* distance must be positive */
        printf( "\n\n\tERROR -- distance must be positive.\n" );
     else {
        count_walks = walk_recur( distance );
        printf( "\n\n\tThe robot can walk %d meters in %d ways.\n",
              distance, count_walks );
     }

     return EXIT_SUCCESS;
}

int  walk_recur( int dist )
{
     /* base cases: 1 meter -- 1 way, 2 meters -- 2 ways */
     if ( dist <= 2 )
        return dist;

     /* recursive call -- walk( dist - 1 ) + walk( dist - 2 ) */
     return walk_recur( dist - 1 ) + walk_recur( dist - 2 );
}