Where does this compiling error come from?

Question

I am getting quite frustrated right now, and the main source of my frustration is the following error:

LogicalAutomaton.java:16: error: cannot find symbol
        Cellular[i][j] = new Cellular (null, Cellular[i+1][j], null, Cellular[i][j+1]);
        ^
symbol:   variable Cellular
location: class LogicalAutomaton

The class hierarchy is the following:

home --> code --> Automata --> automata

And here is the code:

This is the class Cellular.java, in home/code/Automata/automata:

package automata;

public class Cellular {

  private int state;
  private Cellular upper, lower, left, right;

  public Cellular (Cellular upper, Cellular lower, Cellular left,Cellular right) {
    this.state = 0;
    this.upper = upper;
    this.lower = lower;
    this.left = left;
    this.right = right;
  }

}

And this is the class LogicalAutomaton.java, in home/code/Automata:

import automata.Cellular;
import java.util.Arrays;

public class LogicalAutomaton extends Cellular {

  public static void main (String[] args) {

    int n = 3;
    Cellular[][] a = new Cellular[n][n];

    for (int i = 0; i < n; i++) {
      for (int j = 0; j < n; j++) {
        if (i == 0) {
          if (j == 0) {
            Cellular[i][j] = new Cellular (null, Cellular[i+1][j], null, Cellular[i][j+1]);
          }
          else {
            if (j == n-1) {
              Cellular[i][j] = new Cellular (null, Cellular[i+1][j], Cellular[i][j-1], null);
            }
            else {
            Cellular[i][j] = new Cellular (null, Cellular[i+1][j], Cellular[i][j-1], Cellular[i][j+1]);
            }
          }
        }
      }
    }

  }

}

The code of LogicalAutomaton.java is much longer, but the main idea is to get access to the array of Cellular objects in order to initialize them, and each time I try to do this, it throws me said error. Funnily enough, the compiler does not lament the declaration of the Cellular array.

Do you have any idea where I might have done wrong?

Thank you in advance!

Edit:

Sorry for the clumsy question; here is part of the faulty code.

Answer 1

You define your array as

Cellular[][] a = new Cellular[n][n];

but then later on, you use

Cellular[i][j] = new Cellular (null, Cellular[i+1][j], null, Cellular[i][j+1]);

when in fact, you should be using

a[i][j] = new Cellular (null, Cellular[i+1][j], null, Cellular[i][j+1]);

The error message you are getting

LogicalAutomaton.java:16: error: cannot find symbol Cellular[i][j] = new Cellular (null, Cellular[i+1][j], null, Cellular[i][j+1]); ^ symbol: variable Cellular location: class LogicalAutomaton

is saying I cannot find a variable named Cellular, not that I cannot find the class. This is because you have not defined a variable called Cellular , the variable you have defined is called a .

Answer 2

This problem is because of accessibility. The Cellular class is not accessible in the LogicalAutomoton class. Check your CLASSPATH variable and check whether the import statement is correct.