Question

所以我试图创建一个基本上反转某个输入字符串的对象。我能够让它反转单词顺序，但我需要让它使用堆栈来反转单词本身，这是我将代码输入堆栈的代码。

public class Reverser
{
   private Stack<String> stack;

   public Reverser()
   {
     stack = new Stack<String>();
   }

   public String evaluate(String expr)
   {
     Scanner in = new Scanner(expr);

     char letter;
     String sentence="";
     String rSent="";
     String word="";

     while(in.hasNext())
     {
       sentence = in.next();

       for (int i = 1; i <= sentence.length(); i++)
       {
           while (i <= sentence.length())
           {
             letter = sentence.charAt(i);
             word += letter;
           }
          stack.push(word);        
        }
     }
     while (!stack.isEmpty())
     {
     word = stack.pop();
     rSent += word;
     }
   return rSent;
   }  
}

它没有问题编译好，但是当我运行我的驱动程序时

 public class StringReversing
  {
     public static void main(String[] args)
     {
       String sentence, result, again;

      Scanner in = new Scanner(System.in);

      do
      {
         Reverser evaluator = new Reverser();
         System.out.println("Please enter a sentence");
         sentence = in.nextLine();

         result = evaluator.evaluate(sentence);
         System.out.println();
         System.out.println("Your sentence reversed is:");
         System.out.println(result);

         System.out.println("Would you like to reverse another sentence [Y/N]?");
         again = in.nextLine();
         System.out.println();
      }
      while (again.equalsIgnoreCase("y"));
   }
}

现在我输入一个句子而我什么都没得到。我错过了什么吗？

Answer 1

你得到一个无限循环：

       for (int i = 1; i <= sentence.length(); i++)
       {
           while (i <= sentence.length())
           {
             letter = sentence.charAt(i);
             word += letter;
           }
          stack.push(word);        
        }

内部while循环是无限循环，因为我将永远相同且低于sentence.length()。

java中的数组基于零。你for循环从零开始。

Answer 2

这不会解决您的要求吗？

String input = "I like this CAFEBABE.";
System.out.println("reversed: " + new StringBuilder(input).reverse());

反转字符串堆栈java

2 个答案: