For "The difference between loops and recursion in Java and C on a Raspberry Pi" -> https://www.youtube.com/watch?v=TU7P5mqbo5Q

Recursion.c

/* Recursion vs loops example.
   (c) G J Barnard May 2013
   License:
   http://creativecommons.org/licenses/by-nc-nd/3.0/
 */
#include <stdio.h>
#include <sys/time.h>

unsigned char aNumber = 42;

void ALoop(unsigned char number)
{
   while (number <= aNumber) 
   {
      printf(".");
      number++;
   }
   printf("done\n");
}
   
void ARecursion(unsigned char number) 
{
   printf(".");
   number++;
   if (number <= aNumber) 
   {
      ARecursion(number);
   }
   else 
   {
      printf("done\n");
   }
} 

int main() 
{
   struct timeval start, end;
   unsigned long duration = 0;
      
   printf("Loop method:\n");
   gettimeofday(&start, NULL);
   ALoop(0);
   gettimeofday(&end, NULL);
   duration = ((end.tv_sec - start.tv_sec) * 1000000) + end.tv_usec - start.tv_usec;
   printf("Took: %lu micro seconds.\n", duration);
      
   printf("Recursion method:\n");
   gettimeofday(&start, NULL);
   ARecursion(0);
   gettimeofday(&end, NULL);
   duration = ((end.tv_sec - start.tv_sec) * 1000000) + end.tv_usec - start.tv_usec;
   printf("Took: %lu micro seconds.\n", duration);
}

Recursion.java

// Recursion vs loops example.
// (c) G J Barnard May 2013
// License:
// http://creativecommons.org/licenses/by-nc-nd/3.0/

public class Recursion 
{
   private byte aNumber = 42;
   
   public static void main(String args[]) 
   {
      Recursion us = new Recursion();
      long currentTime;
      
      System.out.println("Loop method:");
      currentTime = System.nanoTime();
      us.ALoop((byte)0);
      System.out.println("Took: " + ((System.nanoTime() - currentTime) / 1000) + " micro seconds.");
      
      System.out.println("Recursion method:");
      currentTime = System.nanoTime();
      us.ARecursion((byte)0);
      System.out.println("Took: " + ((System.nanoTime() - currentTime) / 1000) + " micro seconds.");
   }
   
   public void ALoop(byte number)
   {
      while (number <= aNumber) 
      {
         System.out.print(".");
         number++;
      }
      System.out.println("done");
   }
   
   public void ARecursion(byte number) 
   {
      System.out.print(".");
      number++;
      if (number <= aNumber) 
      {
         ARecursion(number);
      }
      else 
      {
         System.out.println("done");
      }
   }
}