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MidPointFindingKarel – My Solution

I had a pretty challenging two weeks of solving this problem. I finally found a solution. I am so relieved.


/*
 * File: MidpointFindingKarel.java
 * -------------------------------
 * When you finish writing it, the MidpointFindingKarel class should
 * leave a beeper on the corner closest to the center of 1st Street
 * (or either of the two central corners if 1st Street has an even
 * number of corners).  Karel can put down additional beepers as it
 * looks for the midpoint, but must pick them up again before it
 * stops.  The world may be of any size, but you are allowed to
 * assume that it is at least as tall as it is wide.
 */


import stanford.karel.*;

public class MidpointFindingKarel extends SuperKarel {
	public void run(){

		/*
		 * Pseudocode
		 * 1.laybeepers
		 * 2.pick them up one end to the other
		 *
		 * Decomposition
		 *  * solves one problem
		 *  * 1-15 lines
		 *  * good names
		 *  * comments /preconditions
		 *  *          /postconditions
		 *
		 */
		LayBeepers();
		BackToStart();

		/* FindTheMiddle
		 * here is the method that
		 * does the work
		 */
		FindTheMiddle();
	}

	/*
	 * LayBeeper
	 * put beepers from one end to the other
	 * pre: unlimited beepers, front is clear
	 * post: wall in front, beeper where iam standing
	 */
	private void LayBeepers(){
		while(frontIsClear()){
			putBeeper();
			move();
		}
		putBeeper();
	}

	/* BackToStart
	 * moves Karel to the starting position
	 * pre: front is blocked
	 * post:front is clear
	 */
	private void BackToStart(){
		turnAround();
		MoveToWall();
		turnAround();
	}

	/* MoveToWall
	 * keep moving until karel hits a wall
	 * pre: front clear
	 * post : front blocked
	 */
	private void MoveToWall(){
		while(frontIsClear()){
			move();
		}
	}

	/* FindTheMiddle
	 * Finds the midpoint of a line
	 * Pre: beepers present in front
	 * post: no more beepers in front
	 *
	 */
	private void FindTheMiddle(){
		if(beepersPresent()){
			pickBeeper();
			}
		while(noBeepersPresent()){
			GotoTheOtherEnd();
			if(frontIsClear()){
				checkabeeper();
			}
			pickBeeper();
		}
	}

	/*
	 * Gootheotherend
	 * traverse the line of beepers
	 */
	private void GotoTheOtherEnd(){
		FirstBeeper();
		EndingBeeper();
	}

	/* FirstBeeper
	 * go to the first beeper
	 */
	private void FirstBeeper(){
		if(noBeepersPresent()){
			move();
		}
	}

	/* endingbeeper
	 * check the lastbeeper
	 *
	 */
	private void EndingBeeper(){
		while(frontIsClear()){
			move();
		}
		turnAround();

		while(noBeepersPresent()){
			move();
		}
	}

	/* checkabeeper
	 * checks if there is still a beeper for the last
	 * time
	 */
	private void checkabeeper(){
		if(beepersPresent()){
			move();
			if(beepersPresent()){
				MoveBack();
			} else {
				MoveBack();
				putBeeper();
			}
		}
	}

        /* Moveback
         *
         */
	private void MoveBack(){
		turnAround();
		move();
		turnAround();
	}
}
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CheckerBoardKarel – CS106a,Assignment 1,Problem 3

Eureka! I solved it! Works in all worlds. I didn’t put any comments because the code is self explanatory.

/*
 * File: CheckerboardKarel.java
 * ----------------------------
 * When you finish writing it, the CheckerboardKarel class should draw
 * a checkerboard using beepers, as described in Assignment 1.  You
 * should make sure that your program works for all of the sample
 * worlds supplied in the starter folder.
 */

import stanford.karel.*;

public class CheckerboardKarel extends SuperKarel {

	public void run(){
		turnLeft();
		for(int i=0;i<32;i++){
			putBeeper();
			skip();
		}
	}
	
	private void skip(){
		if(frontIsClear()){
			move();
			//doubleskip();
		}
			
		if(frontIsBlocked()){
			if(facingNorth()){
				if(beepersPresent()){
					skipright();
				} else {
					movedown();
				}
				
			} else {
				if(facingSouth()){
					if(beepersPresent()){
						skipleft();
					} else {
						moveup();
					}
				} 
			}
			
		} else {
			move();
		}
	}
	
	private void moveup(){
		turnLeft();
		move();
		turnLeft();
	}
	
	private void movedown(){
		turnRight();
		move();
		turnRight();
	}
	
	private void doubleskip(){
		move();
		move();
	}
	
	private void skipright(){
		moveright();
		moveright();
	}
	
	private void skipleft(){
		moveleft();
		moveleft();
	}
	
	private void moveright(){
		turnRight();
		if(frontIsBlocked()){
			moveleft();
		} else {
			move();
		}
	}
	
	private void moveleft(){
		turnLeft();
		if(frontIsBlocked()){
			moveright();
		} else {
			move();
		}
	}
	
	
	
}
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Karel the Robot Assignment 1 Problem 2

It looks like I got the assignment solved. It looks a bit like spaghetti code but it works on the default world.

/*
 * File: StoneMasonKarel.java
 * --------------------------
 * The StoneMasonKarel subclass as it appears here does nothing.
 * When you finish writing it, it should solve the "repair the quad"
 * problem from Assignment 1.  In addition to editing the program,
 * you should be sure to edit this comment so that it no longer
 * indicates that the program does nothing.
 */

import stanford.karel.*;

public class StoneMasonKarel extends SuperKarel {

	public void run(){
		//iterate 13 times(checking 13 columns)
		for(int i=0;i<13;i++){
			check();
			fixColumn();
			keepmoving();
		}
                //pseudocode
		//go up the column
		//check if there is a beeper
		//if there is one
		//go back to the start and
		//fill in the beeper
		//go check the next column
		//repeat
	}

// move to the wall
	private void movetowall(){
		while(frontIsClear()){
			move();
		}
	}

//keep karel moving through the next column
	private void keepmoving(){
		if(frontIsBlocked()){
			if(facingNorth()){
				backtostart();
			}
		}
			
		if(facingNorth()){
			turnRight();
			move();
			//turnRight();
		}
		if(facingSouth()){
			turnLeft();
			move();
			turnLeft();
		}
		if(facingWest()){
			turnAround();
			move();
		}
		
	}

//skip a beeper
	private void skipbeeper(){
		if(beepersPresent()){
			move();
		}
	}

//fix the broken column
	private void fixColumn(){
		backtostart();
		while(frontIsClear()){
			skipbeeper();
			while(noBeepersPresent()){
				
				if(frontIsClear()){
					while(noBeepersPresent()){
						putBeeper();
						move();
					}
				} else {
					if(noBeepersPresent()){
						putBeeper();
					}
					turnAround();
					movetowall();
				}		
			}
		}		
	}

	//move to the next column
	private void nextcolumn(){
		turnLeft();
		move();
		turnLeft();

	}
	
	//back to starting position
	private void backtostart(){
		turnAround();
		movetowall();
		turnAround();
	}
	
	//check if this a column that needs fixing
	private void check(){
		if(facingEast()){
			turnLeft();
		}
		while(noBeepersPresent()){
			if(frontIsClear()){
				move();
			} else {
				turnAround();
				movetowall();
				nextcolumn();
				backtostart();
			}
		}
	}

}
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Getting stuck ?!?

stuck!


* File: StoneMasonKarel.java
 * --------------------------
 * The StoneMasonKarel subclass as it appears here does nothing.
 * When you finish writing it, it should solve the &quot;repair the quad&quot;
 * problem from Assignment 1.  In addition to editing the program,
 * you should be sure to edit this comment so that it no longer
 * indicates that the program does nothing.
 */

import stanford.karel.*;

public class StoneMasonKarel extends SuperKarel {

	public void run(){
		while(frontIsClear()){
			turnLeft();
			movetowall();
			keepmoving();
		}
	}
	
	private void movetowall(){
		while(frontIsClear()){
			move();
		}
	}

	private void keepmoving(){
		if(notFacingEast()){
			turnRight();
		}
		nextcolumn();
	}
	
	private void fixColumn(){
		while(noBeepersPresent()){
			putBeeper();
			move();
		}
		backtostart();
	}
	
	private void nextcolumn(){
		turnRight();
		move();
		turnLeft();
//		turnLeft();
//		move();
	}
	
	private void backtostart(){
		turnAround();
		movetowall();
		turnAround();
	}
	
	private void check(){
		while(noBeepersPresent()){
			move();
		}
		//backtostart();
	}
//	private void fix(){		
//		if(beepersPresent()){
//			//backtostart();
//			fixColumn();
			
//			turnAround();
//			movetowall();
//		}
		
//	}

}

how to iterate??

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The first assignment – CollectNewsPaperKarel

Posting my solution to the problem number 1 of assignment 1 of CS106a. Hoping for some feedback to this.

import stanford.karel.*;

public class CollectNewspaperKarel extends SuperKarel {

		public void run(){
			MoveToNewsPaper();
			pickBeeper();
			MoveBackToStart();
		}


		private void MoveToNewsPaper(){
			while(frontIsClear()){
				move();
			}
			turnRight();
			move();
			turnLeft();
			move();
			
		}

		private void MoveBackToStart(){
			turnAround();
			move();
			turnRight();
			move();
			turnLeft();
			while(frontIsClear()){
				move();
			}
			turnAround();

		}
}