Question

对于学校我必须制作一个能够接受字符串输入并计算1“a”等元音量的扫描仪。我的问题是，当我输入一个字符串时，它不会通过循环和我可以连续输入，输入什么都不做。（我正在使用BlueJ进行编码）。谢谢你的帮助！

package VowelCounter;

/**
 * Description:
 * Author: Jack Cannon
 * Date: 11/15/16
 */

import java.util.Scanner;
public class VowelCounter
{
public static void main(String [] args)
{
     Scanner input = new Scanner(System.in);
     //Prompt the user to enter a phrase 
     System.out.println("Type in a sentence.");
     String phrase = input.nextLine();
     //as long as the string isn't "quit", 
     //count the vowels in the string.
     int length = phrase.length();
     while(phrase != "quit")
    {
         int a = 0;
         int e = 0;
         int i = 0;
         int o = 0;
         int u = 0;  
       for(int c = 0; length < 1; length++)
       {  
           char vowels = phrase.charAt(c);
         if(vowels == 'a')
         {
         }
         else if(vowels == 'e')
         {
         }
         else if(vowels == 'i')
         {
         }
         else if(vowels == 'o')
         {
         }
         else if(vowels == 'u')
         {
         }
       }
   }    
   System.out.println("There are " + 'a' + "a's");
   System.out.println("There are " + 'e' + "e's");
   System.out.println("There are " + 'i' + "i's");
   System.out.println("There are " + 'o' + "o's");
   System.out.println("There are " + 'u' + "u's");
   //print out the count of the vowels for this string.      
   //prompt the user for another phrase.
   }
  }

Answer 1

您在上面分享的代码存在一些问题。

首先，您的while循环的条件为phrase != "quit"。出于两个原因，这是错误的。第一个是这不是你如何比较java中的字符串。为此，请参阅this。第二个原因是你永远不会在while循环中更改变量phrase，因此这会导致无限循环，因为phrase永远不会“退出”，除非这是用户输入的内容如果你只需要用户输入一次，我认为不需要这个while循环。

你的代码错误的第二个原因是你的for循环中的if语句（看看当前char是什么字符）什么都不做。在这一点上，它们只是空代码块。很可能你需要做的是增加适当的元音计数器。

最后，您在打印行中使用了不正确的字符串连接方法。在Java中连接的正确方法如下：

"There are " + a + "a's" // a = 1
=> "There are 1 a's"

使用单引号是不正确的;如果你想打印字母'a'，你会使用它，如下所示：

"There are a a's"

Answer 2

这应该解决你的问题，我只在循环中添加了2个if语句，你可以添加其余的。

public static void main(String [] args){
    Scanner input = new Scanner(System.in);
    //Prompt the user to enter a phrase 
    System.out.println("Type in a sentence.");
    String phrase = input.nextLine();
    //as long as the string isn't "quit", 
    //count the vowels in the string.
    int length = phrase.length();
    int a = 0;
    int e = 0;
    int i = 0;
    int o = 0;
    int u = 0;  
    while(!phrase.equals("quit")){
        for(int c = 0; c<length; c++){  
            char vowels = phrase.charAt(c);
            if(vowels == 'e'){
                e++;
            }
            else if(vowels == "o"){
                o++;
            }
        }
        System.out.println("There are " + a + "a's");
        System.out.println("There are " + e + "e's");
        System.out.println("There are " + i + "i's");
        System.out.println("There are " + o + "o's");
        System.out.println("There are " + u + "u's");
        System.out.println("enter another sentence");
        phrase = input.nextLine();
    }    
}

Java代码不处理输入

2 个答案: