import java.util.*;
public class Test{
  public static void main(String[] args){
    ArrayList aa1=new ArrayList();
    System.out.println("大小为"+aa1.size());
    Xs xs1=new Xs("悟空",15,90);
    Xs xs2=new Xs("八戒",13,70);
    Xs xs3=new Xs("沙僧",14,75);
    Xs xs4=new Xs("小白龙",20,80);
    aa1.add(xs1); //增加 
    aa1.add(xs2);
    aa1.add(xs3);
    System.out.println("大小为"+aa1.size());
    for(int i=0;i<aa1.size();i++){ //遍历
      Xs tv=(Xs)aa1.get(i);
      System.out.println("第"+(i+1)+"个学生姓名是"+tv.getXingming());
    }
  }
}
class Xs{
  private String xingming;
  private int xuehao;
  private int chengji;
  
  Xs(String xingming,int xuehao,int chengji){
    this.xingming=xingming;
    this.xuehao=xuehao;
    this.chengji=chengji;
  }
  public String getXingming(){
    return xingming;
  }
  public int getXuehao(){
    return xuehao;
  }
  public int getChengji(){
    return chengji;
  }
}