Arraylist的操作

package notebook;

import java.util.ArrayList;

public class NoteBook {

private ArrayList<String> notes =new ArrayList<String>();

public void add(String s) {

notes.add(s);

}

public void add(int location,String s) {

notes.add(location,s);

}

public int getSize(){

return notes.size();

}

public String getNote(int index) {

return notes.get(index);

}

//index,下标

public void removeNote(int index) {

notes.remove(index);

}

public String []list(){

String []a=new String[notes.size()];

//for(int i=0;i<notes.size();i++) {

//a[i]=notes.get(i);

//}

notes.toArray(a);//此函数的作用与上面的注解相同

return a;

}

public static void main(String[] args) {

// TODO Auto-generated method stub

NoteBook nb =new NoteBook();

nb.add("first");

nb.add("second");

nb.add(1,"third");

System.out.println(nb.getSize());

System.out.println(nb.getNote(0));

System.out.println(nb.getNote(1));

nb.removeNote(1);

String[]a =nb.list();

for(String s:a) {//对于a里面的每一个String s 来说

System.out.println(s);

}

}

}