Question

I had a question regarding this program I was trying to write.

fin = new FileInputStream (args[0]);
            BufferedReader d = new BufferedReader(new InputStreamReader(fin));
            String str;

            while ((str = d.readLine()) != null) {
                String [] string = str.split(" ");
                System.out.println(string[0]);
                int i=0;
                if(!(string[0].compareTo("INPUT")==0) ||  (string[0].compareTo("OUTPUT")==0))
                {
                    // solution goes here

                }
            }

            fin.close();        

So the question i have is that i am trying to create objects a1, a2, a3 etc of a class (say A) and then add them as a vertex to a graph. Is there a way to define them dynamically? Would this work?

A [] a;
while(condition is true)
{
 a[i].setParameters() // dont worry about this
 graph.addVertex(a[i])
 i++;
}

If not, can you tell me a better way of doing this? When i try this i get local variable not initialized error. I might be missing something trivial

Note:
The project is to design a logic circuit simulator and I am trying to implement a graph styled data structure where nodes depict gates and the interconnects will be edges (I have two classes called gates and interconnects)

Answer 1

It is hard to tell if this fixes all of your problems, since you didn’t provide a precise error message. At least it resolves a problem. You never created objects in your array.
You’d have to know the since upfornt to do so, or you can achieve the desired behavior just like this:

while(condition is true)
{
 A a = new A();
 a.setParameters(); // dont worry about this
 graph.addVertex(a);
 // If you also need it in some kind of array, add it to the array, too.
 // Might be nice to use Vector<A> or List<A> aList = new ArrayList<A>() 
 // since those two can outmaticcaly grow while inserting at the back.
 // Create those outside of the loop if you need them at all.
 i++;
}