我想在Array列表中使用add(int i,T t)方法指定的位置之前,将一个新元素插入到Array List中。而且我想在My Array List Class中使用Clear()方法从Array List中删除所有元素。将元素添加到ArrayList并从ArrayList中删除元素的实现
我该如何执行此操作?
我的数组列表类:
公共类MyArrayList {
private int n=0; //initial size of the array list
private MyArrayListElement<T> firstElement;//the first element of the array list
//Gets the element at index i
private MyArrayListElement<T> getElement(int i){
if(firstElement == null) return null;
int c = 0;
MyArrayListElement<T> x=firstElement;
while(x!=null){
if(c==i) return x;
x=x.getNext();
c++;
}
return null;
}
//Gets the element value at index i
public T get(int i){
MyArrayListElement<T> element = getElement(i);
if(element!=null) return element.getValue();
return null;
}
//Removes the element at index i
public void remove(int i){
MyArrayListElement<T> x= getElement(i);
if(x==null) return;
if(x.getPrevious()!=null){
x.getPrevious().setNext(x.getNext());
}
if(x.getNext()!=null){
x.getNext().setPrevious(x.getPrevious());
}
if(x==firstElement){
firstElement = x.getNext();
}
n--; // decrement the size of the array list
}
//Adds a new element to the end
public void add(T t){
MyArrayListElement<T> element = new MyArrayListElement<T>(t);
if(firstElement == null){
firstElement = element;
}else{
MyArrayListElement<T> lastElement=getElement(n-1); //Get the last element
lastElement.setNext(element); //Add new element to the end
element.setPrevious(lastElement);//Update previous element
}
n++; //increment the size
}
//Returns the number of elements in the array list
public int size(){
return n;
}
public String toString(){
String str ="{";
for(int i=0;i<n;i++){
str+=get(i);
if(i<n-1){
str+=",";
}
}
str+="}";
return str;
}
public void add(int index, T t) {
}
public void clear(){
}
我的数组列表元素类:
公共类MyArrayListElement {
private T value; // This is the data stored in this element
private MyArrayListElement <T> next; // the next element
private MyArrayListElement <T> previous; // the previous element
//Constructor gets an object of type <T> as an argument
public MyArrayListElement(T t) {
value = t; //stores the object in the instance variable "value"
}
public void setValue(T val){
value = val; //change the stored object
}
public void setNext(MyArrayListElement <T> n){
next = n; //set the link to the next element
}
public MyArrayListElement<T> getNext() {
return next; //get the next element
}
public T getValue(){
return value; //get the data stored in this element
}
public MyArrayListElement <T> getPrevious() {
return previous; //get the previous element
}
public void setPrevious(MyArrayListElement <T> previous) {
this.previous = previous; //set the link to the previous element
}
}
这是功课吗?或者你为什么要实现你自己的ArrayList? – keuleJ
如果你真的不想自己做家庭作业,你可以使用任何搜索引擎和搜索双向链表,你会发现算法(在维基百科中有一个伪代码)。 – StephaneM
这不是一个数组列表,正如其名称所示,它是由数组支持的。这是一个链表。 –