#include <stdio.h>
void printnum ( int begin )
{
printf( "%d", begin );
if ( begin < 9 ) /* The base case is when begin is no longer */
{ /* less than 9 */
printnum ( begin + 1 );
}
/* display begin again after we've already printed everything from 1 to 9
* and from 9 to begin + 1 */
if ( begin != 9) {
printf( "%d", begin );
}
}
int main(void){
printnum(0);
return 0;
}