Question

How to invert the letters case in a String uppercase to lowercase and lowercase to uppercase in Java

Answer 1

package javaapplication1;

public class JavaApplication1 {

    public static void main(String[] args) {

        try {

            String s = "Java Programming";
            
            s = InvertLetters(s);
            System.out.println(s);
            
            System.out.println(InvertLetters("php"));

        } catch (Exception e) {
            System.out.println(e.toString());
        }
    }
    static String InvertLetters(String s) {
	
        char[] arr = s.toCharArray();

	    for (int i = 0; i < arr.length; i++) {
	        if (Character.isUpperCase(arr[i])) {
		        arr[i] = Character.toLowerCase(arr[i]);
	        } else if (Character.isLowerCase(arr[i])) {
		               arr[i] = Character.toUpperCase(arr[i]);
	               }
	    }
	    return new String(arr);
    }
}

/*
              
run:
 
jAVA pROGRAMMING
PHP
     
 */

 

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