我一直试图弄清楚这个问题,但无济于事。我想我的代码一定有几个我看不到的问题。我之前使用稍微复杂一点的方式实现了这个,并以更简单的形式编写它来帮助我下面一年中正在苦苦挣扎的朋友,但我最终让自己陷入了困境!
代码如下:
public class ArrayBasedDeque<EltType> implements Deque<EltType> {
private final int CAPACITY = 10;
private int capacity;
private int end;
private EltType deque[];
public ArrayBasedDeque() {
this.capacity = CAPACITY;
deque = (EltType[]) (new Object[capacity]);
}
public EltType first() {
return deque[0];
}
public EltType last() {
return deque[end];
}
public boolean isEmpty() {
return end == 0;
}
public int size() {
return deque.length;
}
public boolean isFull() {
int curSize = size();
return curSize >= capacity;
}
public void insertFirst(EltType first) {
if(!isEmpty()) {
EltType[] tempArray;
tempArray = (EltType[]) new Object[capacity+1];
for (int i=0;i<deque.length;i++) {
tempArray[i+1] = deque[i];
}
deque = tempArray;
}
deque[0] = first;
end++;
}
public void insertLast(EltType last) {
if (isFull()){
EltType[] tempArray;
tempArray = (EltType[]) new Object[CAPACITY+1];
for (int i=0;i<deque.length;i++) {
tempArray[i] = deque[i];
}
}
deque[end] = last;
end++;
}
public EltType removeFirst() {
EltType[] tempArray;
EltType returned = deque[0];
tempArray = (EltType[]) new Object[capacity];
for (int i=1;i<capacity;i++) {
tempArray[i-1] = deque[i];
}
deque = tempArray;
end--;
return returned;
}
public EltType removeLast() {
EltType[] tempArray;
System.out.println(end);
EltType returned = deque[end];
tempArray = (EltType[]) new Object[capacity];
for (int i=0;i<deque.length;i++) {
tempArray[i] = deque[i];
}
deque = tempArray;
return returned;
}
}
问题是当我打电话时
abd.insertFirst( 3 );
abd.insertFirst( 3 );
abd.insertFirst( 3 );
这个,它返回一个错误。
java.lang.ArrayIndexOutOfBoundsException: 11
at ArrayBasedDeque.insertFirst(ArrayBasedDeque.java:37)
at TestABD.main(TestABD.java:7)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:271)
insertLast 方法也是如此。我想不通,希望 stackOverflow 的仔细审视可以帮助我。非常感谢 !