java元音计数器使用开关方法 [英] java Vowel Counter Using Switch Method

问题描述

我应该编写一个简单的 java 应用程序，计算用户输入的字符串中的每个元音并输出每个元音出现的次数.

I am supposed to write a simple java application that counts each vowel in a string entered by the user and outputs the number of time each vowel occurs.

我不明白为什么我的代码会检查字符串中的每个单词.我为每个单词获得了适量的元音.这是我所拥有的:

I don't understand why my code is checking each individual word in my string. I am getting the right amount of vowels for each word. Here is what I have:

import java.util.Scanner;

public class VowelAnalyst
     {
//
//

public static void main (String[] args)
{
String userString;
int aCount = 0, eCount = 0, iCount = 0, oCount = 0, uCount = 0;
char vowels;

Scanner scan = new Scanner (System.in);

System.out.println ("enter string:");
userString = scan.nextLine();

for (int count = 0; count < userString.length(); count++)
{

vowels = userString.charAt(count);

    switch (vowels)
    {
    case 'a':
        aCount++;
        break;

    case 'e':
        eCount++;
        break;

    case 'i':
        iCount++;
        break;

    case 'o':
        oCount++;
        break;

    case 'u':
        uCount++;
        break;

    default:
        System.out.println ("Please enter valid string.");

    }

            System.out.println ("a: " +aCount);
            System.out.println ("e: " +eCount);
            System.out.println ("i: " +iCount);
            System.out.println ("o: " +oCount);
            System.out.println ("u: " +uCount);
        }
    }
}

推荐答案

也许您应该将下面的打印语句移出 for 循环，否则它们将在比较每个字符后打印计数:-

May be you should move your below print statements out of your for loop, else they will print count after every character compared: -

System.out.println ("a: " +aCount);
System.out.println ("e: " +eCount);
System.out.println ("i: " +iCount);
System.out.println ("o: " +oCount);
System.out.println ("u: " +uCount);

更新:-

虽然你这样做的方式还不错，但如果你维护一个Map来存储每个Vowel的计数会更好>.您需要使用每个字符的初始计数 0 来初始化您的 Map，然后在读取每个字符时，如果在 Map 中找到匹配，只需增加计数.

Although the way you are doing is not a bad way, but you would be better if you maintain a Map<Character, Integer> to store the count of each Vowel. You need to initialize your Map with an initial count of 0 for each character, and then on each character read, just increment the count, if match is found in Map.

这是一个示例片段:-

// This is `double-braces` initialization. 
// You can rather initialize your Map in a way you are comfortable with
Map<Character, Integer> vowels = new HashMap<Character, Integer>() {
    {
        put('a', 0);
        put('e', 0);
        put('i', 0);
        put('o', 0);
        put('u', 0);
    }
}; // Note the semi-colon here

然后你在 for 循环中从字符串中读取每个字符的代码:-

And then your code of reading each character from string in for loop: -

for (int count = 0; count < userString.length(); count++)
{
    char ch = userString.charAt(count);
    ch = Character.toLowerCase(ch);

    if (vowels.containsKey(ch)) {
        vowels.put(ch, vowels.get(ch) + 1); 
    }
}

System.out.println(vowels);  // Will print each vowels with respective count

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