Question

How to find missing alphabet characters from a string in Java

Answer 1

import java.util.ArrayList;
import java.util.List;

public class MissingAlphabet {

    public static List<Character> getMissingAlphabetChars(String input) {
        boolean[] present = new boolean[26];

        // Normalize input: lowercase + keep only a..z
        for (char c : input.toCharArray()) {
            char lower = Character.toLowerCase(c);
            if (lower >= 'a' && lower <= 'z') {
                present[lower - 'a'] = true;
            }
        }

        // Collect missing letters
        List<Character> missing = new ArrayList<>();
        for (int i = 0; i < 26; i++) {
            if (!present[i]) {
                missing.add((char) ('a' + i));
            }
        }

        return missing;
    }

    public static void main(String[] args) {
        List<Character> missing = getMissingAlphabetChars("Java Programming");

        for (char c : missing) {
            System.out.println(c);
        }
    }
}

 
 
/*
run:
 
b
c
d
e
f
h
k
l
q
s
t
u
w
x
y
z
 
*/
 

 

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