Print boolean input in a 2d array using for loop

Question

I have an assignment where I need to create a 3x5 array and ask the user for a boolean input. I then need to print the user input into every cell of the array. I'm stuck on how to use a for loop to enter the user input into the array. I also have to do this using methods. My code so far is:

import java.util.*;

public class TrueFalse
{
    static Scanner console = new Scanner(System.in);
    public static void main(String[] args)
    {
        boolean myA[][] = new boolean [5][3];
        popArray(myA);
    }

    public static void popArray(boolean answ, boolean pArray[][])
    {
        System.out.println("Enter true or false.");
        answ = console.nextBoolean();

        for (int i=0; i<pArray.length; i++)
        {
            pArray[i] = answ;
        }
    }
}

Are you getting any errors? If so, what are they?

Code-Apprentice
– Code-Apprentice

2018-02-08 15:27:05 +00:00
Commented Feb 8, 2018 at 15:27 — Code-Apprentice
– Code-Apprentice, Commented Feb 8, 2018 at 15:27

kabanus · Accepted Answer · 2018-02-08 14:18:12Z

1

You're not far off:

for (int i=0; i<pArray.length; i++) {
    for (int j=0; i<pArray[i].length; j++) {
        System.out.println("Enter true or false.");
        pArray[i][j] = console.nextBoolean();
    }
}

will do the trick. Note you defined a matrix with 5 rows and 3 columns, the opposite of what you write in the text. Also note I'm checking nothing here.

answered Feb 8, 2018 at 14:18

kabanus

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Comments

Tim Biegeleisen · Accepted Answer · 2018-02-08 15:48:48Z

1

Your code is not far off. Try iterating over the bounds of the array in your popArray method:

public static void popArray(boolean pArray[][]) {
    for (int r=0; r < pArray.length; ++r) {
        for (int c=0; c < pArray[0].length; ++c) {
            System.out.println("Enter true or false.");
            boolean answ = console.nextBoolean();
            pArray[r][c] = answ;
        }
    }
}

One convenient option for printing your 2D array is Arrays.deepToString(), e.g.

System.out.println(Arrays.deepToString(pArray));

edited Feb 8, 2018 at 15:48

answered Feb 8, 2018 at 14:18

Tim Biegeleisen

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5 Comments

Ryan Asciutto Over a year ago

How would I go about printing the array?

Tim Biegeleisen Over a year ago

@RyanAsciutto Use Arrays.deepToString(), at least this is one easy option.

Ryan Asciutto Over a year ago

Would I put that in the "main" method? What about calling the method "popArray"? That's something I have to do.

Ryan Asciutto Over a year ago

It's giving me the out put where it asks the user for true or false but when I enter one in it just keeps looping it and asking for it again and again. ""Enter true or false. false Enter true or false. true Enter true or false. true""

Tim Biegeleisen Over a year ago

@RyanAsciutto I think we've given you enough help already. See if you can't figure out the rest on your own.

thebishal · Accepted Answer · 2018-02-08 14:20:29Z

0

To make 3*5 array of boolean you should do

 boolean myA[][] = new boolean [3][5];

And make nested loop. and you can index the value to the array variable myA[ i ][ j ]

for(int i=0;i<3;i++){

 for(int j=0;j<5;j++){
    myA[i][j]=false;
  }

}

answered Feb 8, 2018 at 14:20

thebishal

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Comments

MAV · Accepted Answer · 2018-02-08 15:24:18Z

0

In your code you have a two dimensional array but your not assessing it correctly. You can visualized your 2d array as a matrix with 5 rows and 3 columns. So to assess every location you need to specify the row and column numbers. Your code should look like this:

private static int ROWS= 5;
private static int COLUMNS = 3;
static Scanner console = new Scanner(System.in);

public static void main(String[] args)
{
    boolean myA[][] = new boolean [ROWS][COLUMNS];
    popArray(myA);
}

public static void popArray(boolean answ, boolean pArray[][])
{
    System.out.println("Enter true or false.");

    for (int i=0; i<COLUMNS ; i++)
    {
        for (int j=0; j<ROWS; j++)
        {
            pArray[i][j] = console.nextBoolean();
        }

    }
}

edited Feb 8, 2018 at 15:24

answered Feb 8, 2018 at 14:31

MAV

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