import java.util.*; public class NoteBook { private ArrayList<String> Records; private int savedNumbersOfRecords; public NoteBook(){ Records= new ArrayList<String>(); savedNumbersOfRecords=0; } //增加一条记录 public int saveRecord(String string){ Records.add(string); return ++savedNumbersOfRecords; } //获取记录数目 public int getSavedNumbersOfRecords(){ return savedNumbersOfRecords; } //获取某条记录 public String getRecordByIndex(int index){ return Records.get(index); } //删除某条记录 public int deleteRecordByIndex(int index){ Records.remove(index); return --savedNumbersOfRecords; } //列出所有记录 public void listAllRecords(){ System.out.println("笔记本记录列表:"); for(int i=0;i<savedNumbersOfRecords;i++){ System.out.println(this.getRecordByIndex(i)); } System.out.println("笔记本列表打印完毕"); } public static void main(String[] args){ NoteBook noteBook= new NoteBook(); //添加记录 noteBook.saveRecord("第一条记录"); noteBook.saveRecord("第二条记录"); noteBook.saveRecord("第三条记录"); //获取记录总数 System.out.println("获取记录总数:"+noteBook.getSavedNumbersOfRecords()); //列出记录列表 noteBook.listAllRecords(); //获取第二条记录 System.out.println("获取第二条记录:"+noteBook.getRecordByIndex(1)); //删除第二条记录 noteBook.deleteRecordByIndex(1); //列出记录列表 noteBook.listAllRecords(); } }