I've just completed the 3rd task of the 1st assignment offered by Stanford's programming methodologies (see the full resources for it here too).
I just need some helpful feedback on how my code can be better (decomposition-wise) and whether or not my code is comprehensible and readable.
I'm also unsure about the pre-conditions and post-conditions. Can someone please elaborate more on that? Is a pre-condition basically where the program is at when attempting the method and the post-condition just a result of the actual method?
I need all the criticism and feedback I can get.
/* File: CheckboardKarel.java
* ---------------------------
* This program will basically go through an entire row and land checkers on every 2nd cell.
* This process will be alternated on each row.
*/
import stanford.karel.*;
public class CheckerboardKarel extends SuperKarel {
public void run() {
while (facingWest() || facingEast()) {
if (frontIsBlocked()) {
turnKarelNorth();
} //end if
transverseRow();
transverseEvenRow();
} //end while
}
/*
* Method: turnKarelNorth
* ----------------------
* Pre-condition: The program is in a 8x1 (1 column) world and Karel has no choice but to turn north
* Post-condition: This makes Karel turn left and face north
*/
private void turnKarelNorth() {
putBeeper();
turnLeft();
moveUpwards();
}
/*
* Method: moveUpwards
* ----------------------
* This makes Karel lay down the beepers every 2 moves
*/
private void moveUpwards() {
while (facingNorth()) {
move();
move();
putBeeper();
}
}
/*
* Method: transverseRow
* ----------------------
* Pre-Condition:Karel is facing east and is ready to place the beeprs on the first odd row
* Post-Condition: Karel places all the beepers every 2 steps on the first row
*/
private void transverseRow() {
while (facingEast()) {
putBeeper();
move();
isFrontClear();
isFrontBlocked();
} // end while
}
/*
* Method: isFrontClear (if statements)
* ----------------------
* This checks whether Karel is being obstructed.
* She takes anther move if the front is clear.
* Otherwise, if she is blocked, she executes placeBeeperOnNextRow
*/
private void isFrontClear() {
if (frontIsClear()) {
move();
} // end if
else if (frontIsBlocked()) {
placeBeeperOnNextRow();
} // end else
}
/*
* Method: isFrontBlocked (if statement)
* ----------------------
* This checks whether Karel is being obstructed.
* She puts the beeper and places a final beeper on the row.
*/
private void isFrontBlocked() {
if (frontIsBlocked()) {
putBeeper();
placeLastBeeperOnRow();
}
}
/*
* Method: placeLastBeeperOnRow (if statement)
* ----------------------
* This checks if Karel is facing east
*/
private void placeLastBeeperOnRow() {
if (facingEast()) {
ascendOnOddColumn();
}
}
/*
* Method: placeBeeperOnNextRow (if)
* ----------------------
* This method makes Karel ascend at the end of an even column only if she is facing east
*/
private void placeBeeperOnNextRow() {
if (facingEast()) {
ascendOnEvenColumn();
}
}
/*
* Method: ascendOnEvenColumn
* ----------------------
* This method makes Karel climb up the row and place a beeper on the new row
*/
private void ascendOnEvenColumn() {
turnLeft();
move();
putBeeper();
turnLeft();
move();
}
/*
* Method: ascendOnOddColumn
* ----------------------
* This method makes Karel
* climb up the row and place a beeper on the new row
*/
private void ascendOnOddColumn() {
turnLeft();
move();
turnLeft();
}
/*
* Method: transverseEvenRow
* ----------------------
* Pre-condition: Karel lays the checkers on the first row and is now on the 2nd row
* Post-condition: Karel lays the checkers alternately on every 2 steps
*/
private void transverseEvenRow() {
while (facingWest()) {
move();
putBeeper();
isFrontClear();
isFrontBlockedForEvenRow();
}
}
/*
* Method: isFrontBlockedForEvenRow
* ----------------------
* This checks whether Karel (on an even row) is being blocked
* It is in between the steps to help Karel move step-by-step without hitting a wall (which would break the loop)
*
* */
private void isFrontBlockedForEvenRow() {
if (frontIsBlocked()) {
turnRight();
move();
turnRight();
} //end if
}
}
