java - 无限循环，不会以while循环结束

Question

好吧，我已经编写了这个程序，它将计算某些字母和空格，我想要它做的是让用户继续输入短语，并且它继续循环，直到用户输入 quit 终止。我无法确定将 while 循环放在哪里。我知道我应该将所有循环嵌套在 while 循环下，当我这样做时，程序会进入无限循环。

import java.util.Scanner;

public class Count
{
  public static void main (String[] args)
  {
      String phrase;    // a string of characters
      int countBlank;   // the number of blanks (spaces) in the phrase 
      int length;       // the length of the phrase
      char ch;         // an individual character in the string
        int countA=0,countE=0,countS=0,countT=0;


    Scanner scan = new Scanner(System.in);
      // Print a program header
      System.out.println ();
      System.out.println ("Character Counter");
      System.out.println ();

      // Read in a string and find its length
      System.out.print ("Enter a sentence or phrase or enter (Quit) to quit: ");
        phrase = scan.nextLine();
while(!phrase.equalsIgnoreCase ("Quit"))
{
        length = phrase.length();

            // Initialize counts
            countBlank = 0;

        // a for loop to go through the string character by character

            for (int i = 0; i < phrase.length(); i++) 
        {
            if(phrase.charAt(i) == ' ') countBlank++;

            switch(ch=phrase.charAt(i)) 
            {
            case 'a':
            case 'A': countA++;
            break;

            case 'e':
            case 'E': countE++;
            break;

            case 's':
            case 'S': countS++;
            break;

            case 't':
            case 'T': countT++;
            break;

        }
     }


      // Print the results
      System.out.println ();
      System.out.println ("Number of blank spaces: " + countBlank);
        System.out.println ("Number of a: " + countA);
        System.out.println ("Number of e: " + countE);
        System.out.println ("Number of s: " + countS);
        System.out.println ("Number of t: " + countT);
      System.out.println ();

  }
 }
}

Answer 1

在 while 循环中，您永远不会阅读下一行。您需要添加

phrase = scan.nextLine();

在“for”循环之后，但仍在“while”循环内。否则，短语将始终是您读入的第一个内容。