Question

JAVA

I need to make it that I can expand the stack for everytime a push operation is performed that would normally cause an overflow, returning a false value. Should accompany 3 nodes initially.

DriverStack.java

public class DriverStack {
  
public static void main (String[] args)
{
  
Stack s = new Stack(3);
Listing l;
Listing l1 = new Listing ("Bill", "1st Avenue", "123 4567");
Listing l2 = new Listing ("Alec", "2nd Avenue", "456 4567");
Listing l3 = new Listing ("James", "3rd Avenue", "367 8896");
Listing l4 = new Listing ("Nico", "4th Avenue", "322 1156");
  
System.out.println(s.pop());
System.out.println(s.push(l1));
System.out.println(s.push(l2));
System.out.println(s.push(l3));
System.out.println(s.push(l4));
  
System.out.println("\n");

System.out.println("----------------All listings with one over flow----------------" + "\n");
  
s.showAll(); //shows listings
  
System.out.println("----------------Tries to pop the Listing '1'----------------" + "\n");

//Three pop operations
l = s.pop();
System.out.println(l.toString());
  
l = s.pop();
System.out.println(l.toString());
  
l = s.pop();
System.out.println(l.toString());


l = s.pop(); //will try to pop an already empty stack
  
System.out.println(l);
System.exit(0);
  
}
  
}

Stack.java

public class Stack
{
private Listing[] data;
private int top;
private int size;
  
public Stack()
{
top = -1;
size = 3;
data = new Listing[3];
}
public Stack (int n)
{
top = -1;
size = n;
data = new Listing[n];
}
  
public void settop()
  
{
top=-1;
}
  
  
public boolean push(Listing newNode)
{
if(top == size - 1)
return false; //overflow
else
{

top = top + 1;
data[top] = newNode.deepCopy();
return true;
}
}
  
public Listing pop()
{
int topLocation;
if(top == -1)
  
return null; //underflow error
else
{
topLocation = top;
top = top - 1;
return data[topLocation];
  
}
}
  
public void showAll()
{
for (int i = top; i >= 0; i--)
System.out.println(data[i].toString());
  
}
  
public void initialStack()
{
top = -1;
}
  
public boolean StackEmpty()
  
{
if(top == -1)
return true;
else
return false;
  
}
  
public boolean StackFull()
  
{
if(top == size-1)
return true;
else
return false;
  
}
  
public Listing peek()

{

if(StackEmpty())

{

System.out.println("Stack is underflow");

return null;

}

else

{

return data[top];

}

}
  
  

  
}

There is one more class called Listing but I dont think anything needs done with that.

Please comment next to the new code that was added, Thank you!

Answer 1

If you have any doubts, please give me comment...

public class Stack {

    private Listing[] data;

    private int top;

    private int size;

    public Stack() {

        top = -1;

        size = 3;

        data = new Listing[3];

    }

    public Stack(int n) {

        top = -1;

        size = n;

        data = new Listing[n];

    }

    public void settop()

    {

        top = -1;

    }

    public boolean push(Listing newNode) {

       if (top == size - 1){

            Listing[] temp = new Listing[size+1];

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

                temp[i] = data[i];

            }

            data = temp;

            size++;

        }

       top = top + 1;

        data[top] = newNode.deepCopy();

        return true;

    }

    public Listing pop() {

        int topLocation;

        if (top == -1)

            return null; // underflow error

        else {

            topLocation = top;

            top = top - 1;

            return data[topLocation];

        }

    }

    public void showAll() {

        for (int i = top; i >= 0; i--)

            System.out.println(data[i].toString());

    }

    public void initialStack() {

        top = -1;

    }

    public boolean StackEmpty()

    {

        if (top == -1)

            return true;

        else

            return false;

    }

    public boolean StackFull()

    {

        if (top == size - 1)

            return true;

        else

            return false;

    }

    public Listing peek() {

        if (StackEmpty()) {

            System.out.println("Stack is underflow");

            return null;

        } else {

            return data[top];

        }

    }

}