Wrong output element of ArrayList

Question

i want to print element from arraylist, but i'm getting wrong output (.A@15db9742)

import java.util.ArrayList;
class A {
int aa;
A(int x) { 
    aa=x;
}   
}
public class test{
public static void main(String[] args){
    A aa = new A(1);
    A ab = new A(2);
    A ac = new A(3);
ArrayList<A> lista = new ArrayList<A>(3);
lista.add(aa);
lista.add(ab);
lista.add(ac);
System.out.println(lista.get(0)); }

What is the expected output? And what is the output you are getting? — Pradeep Simha, Dec 13 '16 at 12:54
You should indent your code properly if you are asking people to try and read it. — khelwood, Dec 13 '16 at 12:54
It is hard to tell what you expect, but maybe this is helpful: [How do I print my Java object without getting “SomeType@2f92e0f4”?](http://stackoverflow.com/questions/29140402/how-do-i-print-my-java-object-without-getting-sometype2f92e0f4) — Jesper, Dec 13 '16 at 12:57
@Simze i'm expecting to get value of first element of an arraylist (1), and i'm getting ".A@15db9742" — bardamu, Dec 13 '16 at 13:00

0xDECAFC0FFEE · Answer 1 · 2017-04-23T08:30:32.533

Assuming your code is supposed to return 1, your issue lies in that your class A doesn't include a toString method

heres some info on toString: toString

insert this method into class A:

public String toString() {
    return Integer.toString(aa);
}

for future reference, try to style your code slightly more clearly so that others could read what you're trying to do

ex:

import java.util.ArrayList;

class A {
    int aa;

    A(int x) {
        aa=x;
    }
}

public class test {
    public static void main(String[] args) {
        A aa = new A(1);
        A ab = new A(2);
        A ac = new A(3);
        ArrayList<A> lista = new ArrayList<A>(3);
        lista.add(aa);
        lista.add(ab);
        lista.add(ac);
        System.out.println(lista.get(0));
    }
}

good luck :D

score 0 · Answer 2 · answered Dec 13 '16 at 13:04

0

You must override toString method in class A:

public String toString() { 
return "aa: " + this.aa;
}

answered Dec 13 '16 at 13:04

Krishnanunni P V

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thanks. it's working now. – bardamu Dec 13 '16 at 13:07

Wrong output element of ArrayList

2 Answers2