Question

我正在编写一个使用两个不同类的程序。一个类包含main方法，另一个类是泛型类Set，它具有一组使用ArrayList的泛型类型T的项。

该程序找到两组的交集。

我想使用toString（）方法，但是当数据字段不可见时，我不知道如何在这种特定情况下实现它。

import java.util.Random;

//Generic class Set<T>
class Set <T>
{

    ArrayList<T> num = new ArrayList<T>();

    /*Within this class I have (1) an add method, (2) a remove method, 
    and  (3) a method that returns true if the item is in the set and
    false if it is not in the set*/

    //This is the intersection method
    public static <T> Set<T> intersection(Set<T> k, Set<T> p){

        Set<T> abc = new Set<T> ();
        /*I have some other codes here to find the intersection
         of two different sets*/

    return abc;
    }


    @Override
    /*Here is where I am completely lost
    I do not know how to use this method in order to print
    out the intersection of both sets*/

    public String toString() {      
    /*I don't know what to implement here in order to return
    a string that represents the current object*/
    return;
    }
}


public class SecondClass {
//MAIN METHOD
     public static void main(String [] args){   

     /* This program generates random numbers
     for two sets in order to find the
     intersection of both sets. */

     Set<Integer> firstSet = new Set<Integer>();
     Set<Integer> secondSet = new Set<Integer>();
     Set<Integer> result = new Set<Integer>();


     result = Set.intersection(firstSet,secondSet);



      //Display intersection?
      System.out.println(result.toString());

     }
}

Answer 1

您似乎使用ArrayList作为支持数据结构。它有一个很好实现的toString()，那么为什么不直接委托给它呢？

@Override public String toString() { return num.toString(); }

麻烦实现（Java）中的toString（）方法

1 个答案: