ex29.java

来自「JAVA 编程思想 第四版 课后习题答案 代码全！」· Java 代码 · 共 20 行

// holding/Ex29.java
// TIJ4 Chapter Holding, Exercise 29, page 427
/* Fill a PriorityQueue (using offer()) with Double values created using
* java.util.Random, then remove the elements using poll() and display them.
*/
import java.util.*;

class Simple extends Object {}

public class Ex29 {
	public static void main(String[] args) {
		PriorityQueue<Simple> s = new PriorityQueue<Simple>();
		// OK to add one Simple:
		s.offer(new Simple());
		// but no more allowed; get runtime exception:
		// Simple cannot be cast to Comparable:
		s.offer(new Simple());
	}
}