Java学习笔记 2015/4/12

C3:Variables, values , and types Arithmetic expressions. 学习完毕。

C4：Expressions，预习完毕。Lecture_6未听。预计今晚上完。对应本章课后作业明天完成。

Assignment_1 完成。但是无法check.

以下是A1部分，代码，欢迎交流。

/*

 * 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 {private int i = 0;public void run() {while((!leftIsBlocked())) {judgeFirstCorner();completeOneStreet();moveNextStreet();}judgeFirstCorner();completeOneStreet();moveNextStreet();}/* * If the street is a odd street, the first corner should be put a beeper; else it is empty. */ private void judgeFirstCorner() { if(i==1){ i = 0; if(frontIsClear()) { move(); putBeeper();}; } else { i = 1;  putBeeper(); } } /* * control the Karel to check one street/ */ private void completeOneStreet() { while(frontIsClear()) { move(); if(frontIsClear()) { move(); putBeeper(); }; } // while if(facingEast()){ turnAround(); }; if(frontIsClear()) { backToStart(); turnAround(); } else { turnAround(); backToStart(); if(facingWest()) { turnAround();}; } }  /*  * when complete one street. control the karel back to its original port.   */      private void backToStart() {  while(frontIsClear()) {  move();  }      } /* * given that one street is completed, we move to the next street. */ private void moveNextStreet() {         turnLeft(); if(frontIsClear()) {move(); turnRight(); }; }// You fill in this part}

<pre name="code" class="java">/* * File: CollectNewspaperKarel.java * -------------------------------- * At present, the CollectNewspaperKarel subclass does nothing. * Your job in the assignment is to add the necessary code to * instruct Karel to walk to the door of its house, pick up the * newspaper (represented by a beeper, of course), and then return * to its initial position in the upper left corner of the house. */import stanford.karel.*;public class CollectNewspaperKarel extends Karel {public void run() {    move();move();    turnRight();    move();    turnLeft();    move();    pickBeeper();}/* * Turns Karel 90 degrees to the right. */   private void turnRight() {   turnLeft();   turnLeft();   turnLeft();   }    // You fill in this part}

/* * 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 {private int length;private int midLength;public void run() {int halfLength;moveToEnd();turnAround();halfLength = length/2;for(int i=0; i < halfLength ; i++){move();}judgeTheMid();if(midLength==halfLength){turnAround();for(int i=0; i < halfLength ; i++){move();}putBeeper();} else {turnAround();for(int i=0; i < halfLength ; i++){move();}putBeeper();move();putBeeper();}}// You fill in this part/* * when start running, move Karel to the end of the street. * Use the "length" variables to count the length of the street.  */  private void moveToEnd() {    while(frontIsClear()){  move();  length++;  }  } /*  * calculate the correct length of mid ,thinking of the two condition : odd or even.  */   private void judgeTheMid() {   while(frontIsClear()){   move();   midLength++;   }   } }

/* * 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() {    while(frontIsClear()) {    turnLeft();    completeOneAvenue();    turnAround();    backToOriginal();    turnLeft();    getNextAvenue();    }        turnLeft();completeOneAvenue();turnAround();backToOriginal();turnLeft();      }               /*     *repair one avenue from one port to another port.If there     *have been a beeper ,Karel neglect this corner. If haven't      *Karel put a beeper in that corner.     */         private void completeOneAvenue() {while(frontIsClear()) {if(beepersPresent())move();else {putBeeper();move();}}if(!beepersPresent())putBeeper();}  /* * when Karel finish one avenue.For this method ,we control  * Karel back to its original port.   */  private void backToOriginal(){  while(frontIsClear()){ move(); } }   /* *when complete one avenue ,we control Karel move to the next avenue.  */  private void getNextAvenue() {        while(frontIsClear()) {        for(int i=1; i<5; i++)        move();        break;        }} }