Java回文测试仪 [英] Java palindrome tester

问题描述

import java.util.*;
 
class Palindrome
{
  public static void main(String args[])
  {
    String inputString;
    Scanner in = new Scanner(System.in);
 
    System.out.println("Input a string");
    inputString = in.nextLine();
 
    int length  = inputString.length();
    int i, begin, end, middle;
 
    begin  = 0;
    end    = length - 1;
    middle = (begin + end)/2;
 
    for (i = begin; i <= middle; i++) {
      if (inputString.charAt(begin) == inputString.charAt(end)) {
        begin++;
        end--;
      }
      else {
        break;
      }
    }
    if (i == middle + 1) //when or how i will be middle +1 if i<=middle
{
      System.out.println("Palindrome");
    }
    else {
      System.out.println("Not a palindrome");
    } 	
  }
}

我尝试了什么：



以上代码有效。我在互联网上发现这个代码不是我写的代码。但是当我等于中间+ 1时我很困惑。 for循环条件是i <=中。请向我解释。

What I have tried:

above code works. i found this code on internet it is not the code i wrote. but i am confused when i is equal to middle+1. for loop condition is i<=middle. please explain to me.

推荐答案

引用：

但我很困惑等于中+ 1。 for循环条件是i <=中。请向我解释。

but i am confused when i is equal to middle+1. for loop condition is i<=middle. please explain to me.

使用调试器并亲自看看这段代码是如何工作的！



有一个工具可以允许您查看代码正在执行的操作，其名称为调试程序。它也是一个很好的学习工具，因为它向你展示了现实，你可以看到哪种期望与现实相符。

当你不明白你的代码在做什么或为什么它做它做的时候，答案就是答案是调试器。

使用调试器查看代码正在执行的操作。只需设置断点并查看代码执行情况，调试器允许您逐行执行第1行并在执行时检查变量。



调试器 - 维基百科，免费的百科全书 [ ^ ]

http://docs.oracle.com/javase/7/docs/technotes/tools/windows/jdb.html [ ^ ]

https://www.jetbrains.com/idea/help/debugging-your-first-java-application.html [ ^ ]

调试器在这里向您展示你的代码正在做，你的任务是与它应该做的事情进行比较。

调试器中没有魔法，它没有找到错误，它只是帮助你。当代码没有达到预期的效果时，你就会接近一个错误。

Use the debugger and see by yourself how this code works!

There is a tool that allow you to see what your code is doing, its name is debugger. It is also a great learning tool because it show you reality and you can see which expectation match reality.
When you don't understand what your code is doing or why it does what it does, the answer is debugger.
Use the debugger to see what your code is doing. Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.

Debugger - Wikipedia, the free encyclopedia[^]
http://docs.oracle.com/javase/7/docs/technotes/tools/windows/jdb.html[^]
https://www.jetbrains.com/idea/help/debugging-your-first-java-application.html[^]
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't find bugs, it just help you to. When the code don't do what is expected, you are close to a bug.

你的循环增加 i 增加1。它不再是< = middle （即已增加到中间+ 1 ）然后控制掉线循环。任何基础教科书都将解释循环的如何工作。

Your loop increments i by 1. When it is no longer <= middle (i.e. has been incremented to middle+1) then control "falls out" of the loop. Any basic textbook will explain how a for loop works.

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