Method returns wrong result

[Muhammad usman shad]

Salam!
i have developed three classes:

Mainclass.java
GameBoard.java
Graph.java

In Graph class, i have two methods:

addVertice and isVertice.

The isVertice returns true if the two parameters which are passed to it are vertices and false if not.

I call addVertice and pass it two integers values (which are vertices in the graph) in the main of MainClass.

Then i call isVertice method in GameBoard class but it returns false all the time.

It also returns false where it should return true.

The code works well when i call both the methods in the same class but not in my case.

What should i do?

I cannot call both methods in the same class due to given scenario.

Please give some suggestions.

Thanks in advance!

[Rajesh Tarte]

You probably referencing to different objects.

[Christophe Verré]

We'll need to see how you are using addVertice. Are you calling addVertice and isVertice on the same object ? Please show us some code.

[Muhammad usman shad]

Here is the code:

 


class MainClass
{
  public static void main(String args[])
  {
    /* Vertices of Simple Move */

	TheGraph	g	=	new TheGraph();
	g.addVertice(0,1);

	/*	Here the Result is true	*/

	System.out.println(g.isVertice(0,1));

	TheBoard  b	=	new  TheBoard();

	/*	Here the ans is false	*/	

	b.getResult();

  }
}


class TheGraph
{
 int total_vertices;
 boolean adjacencyMatrix_SimpleMove[][];

 TheGraph()
 {
  total_vertices = 25;
  adjacencyMatrix_SimpleMove = new boolean [total_vertices][total_vertices];
 }
       /* Vertices for Simple Move */
 
 public void addVertice(int row, int col)
 {
  if(row >=0 && row < total_vertices && col >= 0 && col < total_vertices)
  {
   adjacencyMatrix_SimpleMove[row][col] = true;
   adjacencyMatrix_SimpleMove[col][row] = true;
  }
 }
 public boolean isVertice(int row, int col)
 {
  if(row >=0 && row < total_vertices && col >= 0 && col < total_vertices)
   return adjacencyMatrix_SimpleMove[row][col];

  else
   return false;
 }
}


class TheBoard
{
	public void getResult()
	{
		TheGraph g = new TheGraph();
		
		System.out.println(g.isVertice(0,1));
	
	}
}

Please tell me what is the solution?

[Christophe Verré]

In TheBoard, you are not adding any vertice. TheGraph g = new TheGraph(); makes a new instance, so you need to call addVertice again.

[Muhammad usman shad]

Can i do it with calling addVertice in one class and isVertice in another class?

[Christophe Verré]

Muhammad usman shad wrote:Can i do it with calling addVertice in one class and isVertice in another class?

Yes, as long as you use the same TheGraph instance. Can you try to figure out how to do it ?

[Muhammad usman shad]

Please you tell me how i can do it!

[Christophe Verré]

You have to think about your design, and it's difficult to help without understanding what you are trying to do. For example, do you need TheGraph instance to be out of TheBoard instance ? Couldn't you make it an instance of TheBoard ?