Code does not work and returns no error (Java)

Question

I’m new to Java, and I can’t run this code:

package exercicio.pkg4;

import java.util.Scanner;

public class Exercicio4 {

    public static void main(String[] args) {

        Scanner ler = new Scanner(System.in);
        int x[] = new int[10];
        int i;
        int resto;

        for(i=1; i<=10; i++)
        {
            System.out.printf("Digite o %iº número\n",i);
            x[i] = ler.nextInt();
        }
        for(i=1; i<=10; i++)
        {
            resto = x[i]%2;
            if(resto == 0)
            {
                System.out.printf("%i <- numero par. ",x[i]);
            }else{
                System.out.printf("%i <- numero impar. ",x[i]);
            }
        }
    }

}

The following messages appear in the output:

Exception in thread "main" java.util.UnknownFormatConversionException: Conversion = 'i'
    at java.util.Formatter$FormatSpecifier.conversion(Formatter.java:2691)
    at java.util.Formatter$FormatSpecifier.<init>(Formatter.java:2720)
    at java.util.Formatter.parse(Formatter.java:2560)
    at java.util.Formatter.format(Formatter.java:2501)
    at java.io.PrintStream.format(PrintStream.java:970)
    at java.io.PrintStream.printf(PrintStream.java:871)
    at exercicio.pkg4.Exercicio4.main(Exercicio4.java:16)
Java Result: 1
CONSTRUÍDO COM SUCESSO (tempo total: 1 segundo)

Answer 1

Your code has two problems:

• First of all there is no %i in the Printf, for values of the type int or Integer use %d and that’s what’s causing UnknownFormatConversionException described in your question;
• Java arrays start at 0 which means that the first Indice is 0 and the last Indice is the tamnaho of the array - 1, if you look at your code you enter the first value at position 1 since the control variable i starts with 1 and goes up to 11 since it uses i <= 10, if not fixed your code will fire a ArrayIndexOutOfBoundsException.

Soon, your code with the fixes would be:

package exercicio.pkg4;

import java.util.Scanner;

public class Exercicio4 {

    public static void main(String[] args) {

        Scanner ler = new Scanner(System.in);
        int x[] = new int[10];
        int i;
        int resto;

        for (i = 0; i < 10; i++) {
            System.out.printf("Digite o %dº número\n", i + 1);
            x[i] = ler.nextInt();
        }

        for (i = 0; i < 10; i++) {
            resto = x[i] % 2;

            if (resto == 0) {
                System.out.printf("%d <- numero par. ", x[i]);
            } else {
                System.out.printf("%d <- numero impar. ", x[i]);
            }
        }

    }

}

Answer 2

Good evening, use %d to decimal no %i