Book(使用了TreeSet，一定要有比较函数)

来源：互联网发布：mac gcc include 编辑：程序博客网时间：2024/06/05 04:57

版本一

class Book implements Comparable{String title;public Book(String t){title=t;}public int compareTo(Object a){Book book=(Book)a;return (title.compareTo(book.title));}public String toString(){return title;}}

import java.util.*;public class TreeTest{public static void main(String [] args){new TreeTest().go();}public void go(){Book b1=new Book("How Cats Work");Book b2=new Book("Remix your Body");Book b3=new Book("Finding Emo");TreeSet<Book> tree=new TreeSet<Book>();tree.add(b1);tree.add(b2);tree.add(b3);System.out.println(tree);}}

版本2

class Book{String title;public Book(String t){title=t;}/*public int compareTo(Object a){Book book=(Book)a;return (title.compareTo(book.title));}*/public String toString(){return title;}}

import java.util.*;public class TreeTest{public static void main(String [] args){new TreeTest().go();}public class BookCompare implements Comparator<Book>{public int compare(Book a,Book b){return a.title.compareTo(b.title);}}public void go(){Book b1=new Book("How Cats Work");Book b2=new Book("Remix your Body");Book b3=new Book("Finding Emo");BookCompare bCompare =new BookCompare();TreeSet<Book> tree=new TreeSet<Book>(bCompare);tree.add(b1);tree.add(b2);tree.add(b3);System.out.println(tree);}}

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