键盘录入一个字符串,按照正序或倒序输出
package treeSet;
import java.util.Comparator;
import java.util.Scanner;
import java.util.TreeSet;
public class TreeSet4 {
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.println("请输入一个字符串");
String line=sc.nextLine();
char[] arr=line.toCharArray();
TreeSet<Character> ts=new TreeSet<>(new Comparator<Character>() {
@Override
public int compare(Character s1, Character s2) {
int num=s1.compareTo(s2); //比较内容
//将这句改为 int num=s2.compareTo(s1); 执行倒序输出//
return num==0? 1:num; //保留重复
}
});
for(char c:arr)
{
ts.add(c);
}
for(Character c:ts)
{
System.out.print(c);
}
}
}
案例;
输入:534261978
输出