Invert characters from a String

Question

I have a code I made to invert a String, but it does not meet what I need. I need it to convert the order of the characters of each sentence.

For example: He converts "Hi guys!" into "! laossep Io". And what I need is for him to convert to "Io! laossep".

My code:

public class ex1 {
        public static void main(String[] args) {
            String palavra = "Abobora Vermelha";
            String resultado=""; 

            for(int x = palavra.length() -1;x>=0;x--){
                resultado = resultado + palavra.charAt(x);
            }
            System.out.println(resultado);
        }
    }

Answer 1

First, that the variable palavra actually contains a phrase. So, to not leave things confused, let’s call it entrada.

You can use entrada.split(" ") to divide the input into the constituent words and then use your algorithm to invert them one by one. I also recommend using a StringBuilder to avoid creating a lot of Stringintermediate s that will be disposed of by the garbage collector and with this cause a relatively bad performance.

Your code goes like this:

public class Ex1 {
    public static void main(String[] args) {
        String entrada = "Abobora Vermelha";
        StringBuilder resultado = new StringBuilder(entrada.length());

        for (String s : entrada.split(" ")) {
            if (resultado.length() != 0) resultado.append(' ');
            for (int x = s.length() - 1; x >= 0; x--) {
                resultado.append(s.charAt(x));
            }
        }
        System.out.println(resultado);
    }
}

See here working on ideone.