public class GameEntry {
private String name;
private int score;
public GameEntry(String n, int s){
name = n;
score = s;
}
public String getName(){
return name;
}
public int getScore(){
return score;
}
public String toString(){
return "(" + name + ", "+ score + ")";
}
}
public class Scoreboard {
private int numEntries = 0;
public GameEntry[] board;
public Scoreboard(int capacity){
board = new GameEntry[capacity];
}
**public void add(GameEntry e){**
//System.out.println(board[numEntries - 1].getScore());
int newScore = e.getScore();
//Is the new entry really a high score
//*****This is the line i refer to as******
if (numEntries < board.length || newScore > board[numEntries - 1].getScore()) {
if (numEntries<board.length) {
numEntries++;
}
//shift any lower scores rightward to make room for the new entry
int j = numEntries - 1;
while(j>0 && board[j-1].getScore()<newScore){
board[j] = board[j-1]; //shift entry from j-1 to j
j--; // and decrement j
}
board[j] = e; // when done add a new entry
}
}
}
我想在Scoreboard类中吸引您注意它的add方法。
我的问题是为什么这段代码不会失败。
第一次运行add方法时,numEntries等于0。因此,在if语句中,board [numEntries-1] .getScore应该获得IndexOutOfBounds。
当我把它放在如果我得到适当的例外之前。 if是否捕获异常?
我已经打印了(numEntries-1)的值,我得到-1。但是在if ot内部似乎并不打扰它。
我指的是第一个if的add方法内部。
if (numEntries < board.length || newScore > board[numEntries - 1].getScore())
最佳答案
简单答案:逻辑或短路评估。
当条件的第一部分(即numEntries < board.length
)评估为true
时,根本不评估||
之后的第二部分。