Java: ArrayList to String?

Question

I try to print reverse of the entering number without any for loop. But I've got some issues with printing the Arraylist. How can I print the Arraylist [3, 5, 4, 1] as 3541 - without brackets, commas and spaces?

If not possible, how can I add my ArrayList elements to stringlist then print?

public static void main(String[] args) {

    int yil, bolum = 0, kalan;
    Scanner klavye = new Scanner(System.in);
    ArrayList liste = new ArrayList();
    //String listeStr = new String();
    System.out.println("Yıl Girin: "); // enter the 1453
    yil = klavye.nextInt();

    do{ // process makes 1453 separate then write in the arraylist like that [3, 5, 4,1]

        kalan = yil % 10;
        liste.add(kalan);
        bolum = yil / 10;
        yil = bolum;

    }while( bolum != 0 );

    System.out.println("Sayının Tersi: " + ....); //reverse of the 1453
    klavye.close();
}

You may want to check out stackoverflow.com/questions/196628/… — Rjbcc58
– Rjbcc58, Commented Oct 22, 2012 at 17:18

assylias · Accepted Answer · 2012-10-22 17:16:16Z

3

Read the entry as a String
Reverse it with String reverse = new StringBuilder(input).reverse().toString();
Optional: parse it to an int if you need to do some calculations with that int.

answered Oct 22, 2012 at 17:16

assylias

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3 Comments

Christian Kuetbach Over a year ago

[1,23] will become 321 insted of 231. I think tht ws the intented output.

assylias Over a year ago

My understanding is that the user enters one number (1453 in the given example) and the goal is to reverse that number (to 3541 in the given example). I might have misunderstood.

Christian Kuetbach Over a year ago

but, wht is, if one of the numbers lrger than 9? I think that is not clear.

chrome · Accepted Answer · 2012-10-22 17:23:30Z

1

public static void main(String[] args) {


    int yil, bolum = 0, kalan;
    ArrayList liste = new ArrayList();
    System.out.println("Yıl Girin: "); // enter the 1453
    yil = 1453;

    String s="";
    do { // process makes 1453 separate then write in the arraylist like that [3, 5, 4,1]

        kalan = yil % 10;
        liste.add(kalan);
        s= s + kalan;  // <------- THE SOLUTION AT HERE  -------

        bolum = yil / 10;
        yil = bolum;

    } while (bolum != 0);

    System.out.println("Sayının Tersi: " + s ); //reverse of the 1453

}

answered Oct 22, 2012 at 17:23

chrome

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1 Comment

Reimeus Over a year ago

StringBuilder would be better here for appending characters but this seems to be most appropriate to solve the overall FIFO problem here so +1!

Kumar Vivek Mitra · Accepted Answer · 2012-10-22 17:28:08Z

1

- Reverse can be easily obtained using Collections.reverse(List<?> l)

Eg:

ArrayList<String> aList = new ArrayList<String>();

Collections.reverse(aList);

- Use For-Each loop to print it out.

Eg:

for(String l : aList){

    System.out.print(l);

}

answered Oct 22, 2012 at 17:28

Kumar Vivek Mitra

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Comments

Christian Kuetbach · Accepted Answer · 2012-10-22 17:22:51Z

0

List strings = ...
List stringsRevers = Collections.reverse(strings);
// Have to reverse the input
// 1,23 -> 231 
// otherwise it would be 321   
StringBuilder sb = new StringBuiler();
for(String s: stringsRevers ){
    sb.ppend(s);
}
String out = sb.toString();

answered Oct 22, 2012 at 17:22

Christian Kuetbach

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