Hi. I'm in a Java class at harvard, and they gave us this assignment to create a function moveKiloMile(); , which moves an on-screen robot 1000 units. We can declare the function by using a function moveMile(); , which moves the robot 8 units. Below is the code that I wrote. I'm trying to find out how to do the kilomile function without using a loop, since the professor says that its relatively short.

class Mover extends UrRobot
{
	void turnAround()
	{
		turnLeft();
		turnLeft();
	}

	void moveMile()
	{
		move();
		move();
		move();
		move();
		move();
		move();
		move();
		move();
	}

	void moveKiloMile()
	{
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();		
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		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
		moveMile();
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		moveMile();
		moveMile();
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		moveMile();		
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		moveMile();
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		moveMile();
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		moveMile();
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		moveMile();
		moveMile();
		moveMile();
		moveMile();
	}

	main
		{
			Mover Karel = new Mover (1, 1, East, 0);
			Karel.turnAround();
			Karel.turnAround();			
			moveMile();
			moveKiloMile();
		}
}

To download the program we created this in, visit http://www.fas.harvard.edu/~libs111 and click the "Karal" button on the left column.

Thanks!

Ian

Oh my goodness gracious! What I suggest is to possibly use a recursive function, since you can't use a loop. This calls a function multiple times until a condition is met. (You pass the parameters for the condition into the function). Tell me if this works:

void moveKiloMile(int i)
{
     if (i > 0)
     {
          moveMile();
          i--;
          moveKiloMile(i);
      }
}

However, in the main function, you will have to call moveKiloMile(1000) to indicate you want to run moveMile 1000 times. Otherwise, you could do moveKiloMile(5) to run moveMile 5 times, and, well, you get the idea. :D Other than that, it works!

Just noticed you wrote this isn't in Java, it's in JKarel. I downloaded the JKarel Users Manual you provided a link to, and it says to do this:

loop(1000)
{
     moveMile();
}

or, alternatively

int i = 0;
while (i < 1000)
{
     moveMile();
     i++;
}

Actually, I would assume if your teacher/professor said not to use a "loop" he was referring to the former and wants you to use "while" instead. However, in real programming, the former refers to a for loop while the later refers to a while loop.

In any case, I'm not sure if you can use the code for the "while" I've provided only because I don't see that JKarel supports variables of any kind - only calling functions.

I don't see how someone can tell you to write something efficient without a loop (in this language anyways). Another way to do it besides recursion is to create a label and jump to it if your language supports it. (Kind of like Basic's GOTO.) Jumps are used more in lower level languages like assembly. This seems to be a higher level one, so a jump wouldn't be the best way but it would work.

According to what I saw of the how-to, no labels are supported either. Just functions and function calls!

According to the how-to, which is basically meant as an "intro to the java language" there is something called loop(x) where x is an integer value, not a variable. Then there is something else called while(condition). When the teachers says don't use a loop, I think he/she means to use a while. According to the how-to, the "while" isn't associated with a "loop". See what I'm saying?

Yes, and quite a good one at that, so I hear. And they count "while's" as loops too. Additionally, there aren't any multiplication functions or variables that can be used.

I'm not actually looking for code, either. More of just the techique as to how to do it.

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