按字母顺序显示ArrayList

Question

我写了一个接受字符串的类，计算字符串中每个字母的出现，然后打印每个字母的出现。我希望按字母顺序显示，但不确定如何执行此操作。

import java.util.ArrayList; // import the ArrayList class

class CryptCmd {

    public static void CryptCmd(String str) {

        ArrayList<String> occurs = new ArrayList<>();

        final int MAX_CHAR = 256;

        // Create an array of size 256 i.e. ASCII_SIZE
        int[] count = new int[MAX_CHAR];

        int len = str.length();

        // Initialize count array index
        for (int i = 0; i < len; i++)
            count[str.charAt(i)]++;

        // Create an array of given String size
        char[] ch = new char[str.length()];
        for (int i = 0; i < len; i++) {
            ch[i] = str.charAt(i);
            int find = 0;
            for (int j = 0; j <= i; j++) {

                // If any matches found
                if (str.charAt(i) == ch[j])
                    find++;
            }

            if (find == 1)
                occurs.add("Number of Occurrence of " + str.charAt(i) + " is: " + count[str.charAt(i)] + "\n");
        }

        System.out.println(String.join("",occurs));

        int total = 0;
        for(int i = 0; i < str.length(); i++) {
            if(str.charAt(i) != ' ')
                total++;
        }
        System.out.println("Total chars is " + total);
    }
}

到目前为止，打印内容以找到信件的顺序显示，即>

"Hello" = 
Number of Occurrence of H is: 1
Number of Occurrence of e is: 1
Number of Occurrence of l is: 2
Number of Occurrence of o is: 1

Total chars is 5
所需的输出是这个，按字母顺序排列，即

"Hello" =
Number of Occurrence of e is: 1
Number of Occurrence of H is: 1
Number of Occurrence of l is: 2
Number of Occurrence of o is: 1

Total chars is 5

我写了一个接受字符串的类，计算字符串中每个字母的出现，然后打印每个字母的出现。我希望按字母顺序显示，但不确定...

Answer 1

它返回是因为H在您的情况下为大写字母，而在ASCII ordering中为小写字母。