// We have a number of bunnies and each bunny has two big floppy ears.
// We want to compute the total number of ears across all the bunnies
// recursively (without loops or multiplication). 
//bunnyEars(0) → 0
//bunnyEars(1) → 2
//bunnyEars(2) → 4
 
#include <stdio.h>
 
// To enable debug messages uncomment #define
#define TEST 1
 
int bunnyEars(int bunnies);
void startTesting();
 
int main(void) {
#ifdef TEST
    startTesting();
#endif
 
	return 0;
}
 
int bunnyEars(int bunnies) {
    if (bunnies == 0) {
        return 0;
    }
    if (bunnies == 1) {
        return 2;
    }
 
    return  2 + bunnyEars(bunnies - 1);
}
 
void startTesting()
{
    int result = 0;
    int i = 0;
 
    for (i = 0; i <= 5; i++) {
         result = bunnyEars(i);
 
         printf("BunnyEars(%d) = %d\n", i, result);
    }
}