import java.util.HashSet;
import java.util.Iterator;
class HashSetTest
{
            HashSet<Student> hs =new HashSet<Student>();
              public void put(Student o)
              {
                       hs.add(o);
              }
              public void print()
              {
                    Iterator<Student> it=hs.iterator();
                    while(it.hasNext())
                    {
                           System.out.println(it.next());  
                    }
              }
            public static void main(String[] args)
            {
                    HashSetTest hs1=new HashSetTest();
                      hs1.put(new Student(1,"fenhua1"));
                      hs1.put(new Student(4,"fenhua4"));
                      hs1.put(new Student(3,"wufeng"));
                      hs1.put(new Student(3,"wufeng"));
                      hs1.print();                       /*我在Student类中虽然重写了hashCode(),equals(),但我在main()中并没有调用他们，为什么我输入两个new Student(3,"wufeng"）对象到 hs1中，最终结果输出的只有一个3 ：wufeng 补充：我已经明白有hashCode()和equals（）方法能得到同一个内存地址，我想问的是，我没调用他们，怎么就实现了new Student(3,"wufeng"在内存中就得到了同一内存地址？
                      
                     
            }
}
class Student 
{
   Integer num;
   String name;
   
   
  
   Student(Integer num, String name)
   {
           this.num=num;
           this.name=name;
   }
   public String toString()
   {
        return num+":"+name;
   }
  public int hashCode()
    {
           return num*name.hashCode();
    }
 /* public boolean equals(Object obj) 
   {

if(obj instanceof Student){
Student s = (Student)obj;
return num == s.num && name.equals(s.name);
}*/
public boolean equals(Object obj) 
{
Student s = (Student)obj;
return num == s.num && name.equals(s.name);
}
}