Java 实例 使用Stack，Queue，for或while循环检查回文串

在本教程中，我们将看到程序来检查给定的String是否是回文。以下是实现目标的方法。

1）使用堆栈

2）使用队列

3）使用for/while循环

程序 1：使用堆栈进行回文检查

import java.util.Stack;import java.util.Scanner;class PalindromeTest {    public static void main(String[] args) {        System.out.print("Enter any string:");        Scanner in=new Scanner(System.in);        String inputString = in.nextLine();        Stack stack = new Stack();        for (int i = 0; i < inputString.length(); i++) {            stack.push(inputString.charAt(i));        }        String reverseString = "";        while (!stack.isEmpty()) {            reverseString = reverseString+stack.pop();        }        if (inputString.equals(reverseString))            System.out.println("The input String is a palindrome.");        else            System.out.println("The input String is not a palindrome.");    }}

输出 1：

Enter any string:abccbaThe input String is a palindrome.

输出 2：

Enter any string:abcdefThe input String is not a palindrome.

程序 2：回顾检查使用队列

import java.util.Queue;import java.util.Scanner;import java.util.LinkedList;class PalindromeTest {    public static void main(String[] args) {        System.out.print("Enter any string:");        Scanner in=new Scanner(System.in);        String inputString = in.nextLine();        Queue queue = new LinkedList();        for (int i = inputString.length()-1; i >=0; i--) {            queue.add(inputString.charAt(i));        }        String reverseString = "";        while (!queue.isEmpty()) {            reverseString = reverseString+queue.remove();        }        if (inputString.equals(reverseString))            System.out.println("The input String is a palindrome.");        else            System.out.println("The input String is not a palindrome.");    }}

输出 1:

Enter any string:xyzzyxxyzzyxThe input String is a palindrome.

输出 2:

Enter any string:xyzThe input String is not a palindrome.

程序 3：使用for循环/While循环和字符串函数charAt

import java.util.Scanner;class PalindromeTest {   public static void main(String args[])   {      String reverseString="";      Scanner scanner = new Scanner(System.in);      System.out.println("Enter a string to check if it is a palindrome:");      String inputString = scanner.nextLine();      int length = inputString.length();      for ( int i = length - 1 ; i >= 0 ; i-- )         reverseString = reverseString + inputString.charAt(i);      if (inputString.equals(reverseString))         System.out.println("Input string is a palindrome.");      else         System.out.println("Input string is not a palindrome.");   }}

输出 1:

Enter a string to check if it is a palindrome:aabbaaInput string is a palindrome.

输出 2:

Enter a string to check if it is a palindrome:aaabbbInput string is not a palindrome.

如果你想在上面的程序中使用While循环，那么用这段代码替换for循环：

int i = length-1;while ( i >= 0){    reverseString = reverseString + inputString.charAt(i);    i--;}