1
問候。除了一項要求外，我已經完成了一所學校的項目。與遺產有關的家庭作業
的要求是：
注意，SeaCreature類定義了不同方向的四個常數。確保使用它們。儘管您可能會認爲它們始終是int類型，但您的代碼不應該依賴於分配給這些常量的特定值。
我看不到這個值。分配的常量值是邏輯上的，並且可以方便地使用隨機返回方向。如果分配的值是四個非連續的數字，這會使代碼真的變得複雜。
下面是在作業中提到的原始SeaCreature類，然後是我的一個使用Random的生物的代碼。除了在每個類別中涉及隨機移動的NORTH，SOUTH，EAST，WEST分配新值之外，是否有更清晰的方法來返回基本方向而不是0-3的值？
非常感謝您的建議，並請詢問是否需要澄清。
import java.util.*;
/**
* Defines the attributes and behaviors common to all SeaCreatures in order to participate
* in the SeaCreature simulation.
*
* Each SeaCreature is represented by a char.
* Each SeaCreature can answer back its char when asked.
* Each SeaCreature can answer its next move, NORTH, SOUTH, EAST, WEST.
*
*/
public abstract class SeaCreature {
private char ch;
/** defined constant to facilitate random movement*/
public static final Random rand = new Random();
/** defined constant to move one unit NORTH */
public static final int NORTH = 0;
/** defined constant to move one unit SOUTH */
public static final int SOUTH = 1;
/** defined constant to move one unit EAST */
public static final int EAST = 2;
/** defined constant to move one unit WEST */
public static final int WEST = 3;
/**
* Construct a SeaCreature object with the given character representation
* @param c the character for this SeaCreature
*/
public SeaCreature (char c){
ch = c;
}
/**
* Answers back the character representation for this SeaCreature
* @return this SeaCreature's initial
*/
public char getChar(){
return ch;
}
/** Answers back the next move for this SeaCreature.
* Must be overridden by subclasses
* @return NORTH, SOUTH, EAST, or WEST
*/
public abstract int getMove();
}
我的海獅類：
/**
* Defines the attributes and behaviors specific to SeaLions in order to participate
* in the SeaCreature simulation.
*
* @author Justin Ashburn
* @version 6/5/2011
*/
public class SeaLion extends SeaCreature {
/** defined char to represent a SeaLion*/
private static final char SEALION = 'L';
/** defined steps before SeaLion cycle repeats*/
private static final int CYCLE_LENGTH = 3;
/** defined steps before SeaLion's first direction*/
private static final int DIRECTION_ONE_LENGTH = 2;
private int directionOne;
private int count;
/**
* Construct a SeaLion object with the given character representation
*/
public SeaLion(){
super(SEALION);
// establishes an initial direction
directionOne = rand.nextInt(4);
count = 0;
}
/** Moves like the 'Knight' chess piece. ie. Picks a random direction, moves 2 times
* in that direction, and then randomly chooses a direction perpendicular to the first
* and moves in that direction once.
*
* @return 0, 1, 2, or 3
*/
public int getMove() {
int direction;
int directionTwo;
// continues with direction one for the appropriate length
if (count < DIRECTION_ONE_LENGTH) {
count ++;
direction = directionOne;
}
// if directionOne was east or west chooses a new north or south direction for last move
else if (count < CYCLE_LENGTH && directionOne > 1) {
directionTwo = rand.nextInt(2);
direction = directionTwo;
// resets count and establishes new direction in next cycle
count = 0;
directionOne = rand.nextInt(4);
}
// if directionOne was north or south chooses a new east or west direction for last move
else {
directionTwo = rand.nextInt(2) + 2;
direction = directionTwo;
// resets count and establishes new direction in next cycle
count = 0;
directionOne = rand.nextInt(4);
}
return direction;
}
}
我不明白這與繼承有什麼關係，除了'extends'關鍵字的存在。 – 2011-06-07 04:22:47
SeaLion延伸SeaCreature。這是繼承。 – Nik 2011-06-07 04:23:40
我看不到你在代碼中使用'const'的地方。是的，你使用的是int值，但不是const。我*認爲*這就是要求所要求的。在這種特殊情況下沒有太多價值，因爲這是一個簡單的概念。但是你的下一個項目可能是那些'常量不那麼簡單 - 也許他們是字符串 - 你怎麼做到隨機1-4？在這種情況下，你應該很容易編寫一個GetRandomDirection（）方法，該方法返回一個INT，並且可以從const中隨機選取？ – Prescott 2011-06-07 04:35:15