How can I fix my code to print "AAADADDA" instead of "DAADAAAAAAADADDA"?

Question

I have the following code:

import java.util.Scanner;
public class Chapter10_NextGeneration {
public static void main(String[]args) {
    Scanner sc=new Scanner(System.in);
    System.out.println("Type in your cell positions(ie 8,A,D,D,A,D,D,A,A,2 - NO SPACES & CASE SENSITIVE): ");
    String positions_str=sc.nextLine();
    sc.close();
    String[] cells=positions_str.split(",");
    String[] next_generation=new String[cells.length-2];
    for(int j=0; j < Integer.parseInt(cells[cells.length-1]); j++) {
    for(int i=1;i<cells.length-1;i++) {
        if(i-1<1) { 
            if(cells[i+1].equals("D")) {
                next_generation[i-1]="D";
            }
            else {
                next_generation[i-1]="A";
            }
        }
        else if(i+1==cells.length-1) {
            if(cells[i-1].equals("D")) {
                next_generation[i-1]="D";
            }
            else {
                next_generation[i-1]="A";
            }
        }
        else if((cells[i-1].equals("A") && cells[i+1].equals("D")) || (cells[i-1].equals("D") && cells[i+1].equals("A"))) {
                next_generation[i - 1]="A";
            }
        else if((cells[i-1].equals("A") && cells[i+1].equals("A")) || (cells[i-1].equals("D") && cells[i+1].equals("D"))) {
                next_generation[i - 1]="D";
            }
    }
        for (int i = 0; i < next_generation.length; i++) {
            cells[i+1]=next_generation[i];
            System.out.print(next_generation[i]);
        }
    }
}

}

I have tried and tried to fix my code, but I can't fix my code to say, AAADADDA. It keeps printing, DAADAAAAAAADADDA. Is there something wrong with my for loops? Or is it something with the content of the loops?

Youre printing the object `next_generation`. I guess you want to print its content? — Moritz Schmidt, Mar 01 '20 at 19:28
just how do i do it is my question, sir. without using the toString method. — boi yeet, Mar 01 '20 at 19:29

Rauññ · Answer 1 · 2020-03-01T19:41:59.153

1

Try to use this!

String nextGenString = String.join(" ", next_generation);

Example:

String [] letters = {"H","E","Y"};
String nextGenString = String.join(" ", letters);
System.out.print(nextGenString); //prints H E Y

edited Mar 01 '20 at 19:41

answered Mar 01 '20 at 19:30

Rauññ

378
3
17

sir, Your code only printed null – boi yeet Mar 01 '20 at 19:38
It works for me. Check the example I wrote for you – Rauññ Mar 01 '20 at 19:41

score 1 · Answer 2 · answered Mar 01 '20 at 19:46

1

Using String.join():

System.out.println(String.join("", next_generation));

Using Arrays.stream().collect():

System.out.println(Arrays.stream(next_generation).collect(Collectors.joining()));

answered Mar 01 '20 at 19:46

CausingUnderflowsEverywhere

1,908
13
33

Nice I didnt know join – Moritz Schmidt Mar 01 '20 at 21:43

score 0 · Answer 3 · answered Mar 01 '20 at 19:33

0

StringBuilder str = new StringBuilder();
for(String ng : next_generation)
{
    str.append(ng);
}
System.out.println(str.toString());

answered Mar 01 '20 at 19:33

adxl

829
1
9
19

score 0 · Accepted Answer · answered Mar 01 '20 at 19:52

You can't directly convert the String[] to string using the function toString().You need to take help of StringBuilder

 public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("Type in your cell positions(ie 8,A,D,D,A,D,D,A,A,2 - NO SPACES & CASE SENSITIVE):");
        String positions_str = sc.nextLine();
        sc.close();
        String[] cells = positions_str.split(",");
        String[] next_generation = new String[cells.length - 2];
        for (int i = 1; i < cells.length - 1; i++) {
            if (cells[i - 1].equals("") || cells[i + 1].equals("")) {
                cells[i - 1] = "D";
                cells[i + 1] = "D";
                if ((cells[i - 1].equals("A") && cells[i + 1].equals("D")) || (cells[i - 1].equals("D") && cells[i + 1].equals("A"))) {
                    next_generation[i] = "A";
                }
                if ((cells[i - 1].equals("A") && cells[i + 1].equals("A")) || (cells[i - 1].equals("D") && cells[i + 1].equals("D"))) {
                    next_generation[i] = "D";
                }
            }
        }
        StringBuilder stringBuilder = new StringBuilder();
        for (String string : next_generation) {
            stringBuilder.append(string);
        }
        System.out.println(stringBuilder.toString());
    }

Hope so it works for you.

How can I fix my code to print "AAADADDA" instead of "DAADAAAAAAADADDA"?

4 Answers4