Question

How to check if a word is all uppercase or lowercase or capitalized in Java

Answer 1

public class CapitalizationChecker {

    public static boolean verifyAllUpperOrAllLowerOrIsCapitalized(String word) {
        int upper = 0;
        int lower = 0;

        for (char ch : word.toCharArray()) {
            if (Character.isLowerCase(ch)) {
                lower++;
            } else if (Character.isUpperCase(ch)) {
                upper++;
            }
        }

        // All lowercase
        if (upper == 0) return true;

        // All uppercase
        if (lower == 0) return true;

        // Only the first letter is uppercase
        if (upper == 1 && Character.isUpperCase(word.charAt(0))) return true;

        // Otherwise, invalid capitalization
        return false;
    }

    /**
     * Runs a test on a given word and prints the result.
     */
    public static void runTest(String word) {
        System.out.println("Testing word: \"" + word + "\"");

        if (verifyAllUpperOrAllLowerOrIsCapitalized(word)) {
            System.out.println("OK");
        } else {
            System.out.println("Error");
        }

        System.out.println();
    }

    public static void main(String[] args) {
        runTest("PROGRAMMING");  
        runTest("programming"); 
        runTest("Programming");  
        runTest("ProGramMing"); 
    }
}



/*
run:

Testing word: "PROGRAMMING"
OK

Testing word: "programming"
OK

Testing word: "Programming"
OK

Testing word: "ProGramMing"
Error

*/

 

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