Java 2Dimensional Boolean Array Values

Question

I'm having a problem with my 2 dimensional boolean array. (or it may be with the logic of printing out the values). I set all of the values in the array to false in the beginning, and then later i print out the values to the screen. When i print them out, they all come up as true.

x=20;
y=10;
boolArray = new boolean[x][y];

for(int c=0;c<x;c++)
{
  for(int i=0;i<y;i++)
  {
    boolArray[c][i] = false;
  }
}

System.out.println("2D Boolean Array:");

for(int a = 0; a < boolArray.length; a++)
{
  for(int b = 0; b < boolArray[a].length; b++)
  {
    if(boolArray[a][b] = true)
    {
      System.out.print("T");
    }
    else if(boolArray[a][b] = false)
    {
      System.out.print("F");
    }
  }
}

what is value of x and y? post full code

Nikolay Kuznetsov
– Nikolay Kuznetsov

2012-12-04 14:49:04 +00:00
Commented Dec 4, 2012 at 14:49 — Nikolay Kuznetsov
– Nikolay Kuznetsov, Commented Dec 4, 2012 at 14:49
you are using = in your if conditions, not ==

jlordo
– jlordo

2012-12-04 14:50:14 +00:00
Commented Dec 4, 2012 at 14:50 — jlordo
– jlordo, Commented Dec 4, 2012 at 14:50

jlordo · Accepted Answer · 2012-12-04 14:51:11Z

1

This is bad:

if(boolArray[a][b] = true)
    {
      System.out.print("T");
    }
    else if(boolArray[a][b] = false)
    {
      System.out.print("F");
    }

you are using the assignment operator = instead of the comparison operator ==

You could change it to

if(boolArray[a][b] == true)
//...
else if(boolArray[a][b] == false)

or nicer

if(boolArray[a][b])
//...
else if(!boolArray[a][b])

or even nicer:

if(boolArray[a][b])
//...
else

answered Dec 4, 2012 at 14:51

jlordo

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Comments

Nikolay Kuznetsov · Accepted Answer · 2012-12-04 14:51:02Z

0

Try this:

    if(boolArray[a][b])
    {
      System.out.print("T");
    }
    else
    {
      System.out.print("F");
    }

With booleans you can do like

if(boolean field)

You have used = assigment instead of == comparison.

answered Dec 4, 2012 at 14:51

Nikolay Kuznetsov

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