CSCI152 L6 P1

///////////////////////////////////////////////////////////////////////////// IntrStack ADT (interface)
public interface IntStack {

    /**
     * Puts the given element on the top of the stack.
     *
     * @param value element to be added on the top of the stack
     */
    public void push(int value);

    /**
     * Removes and returns the top most element of the stack
     *
     * @return the top most element of the stack
     * @throws Exception if the stack is empty
     */
    public int pop() throws Exception;

    /**
     * @return the size of the stack
     */
    public int getSize();

    /**
     * Removes all elements from the stack
     */
    public void clear();

    /**
     * @return a String representation of the stack
     */
    @Override
    public String toString();

}

///////////////////////////////////////////////////////////////////////////////// ArrayIntStack Implementation
public class ArrayIntStack implements IntStack{

    private int[] values;
    private int size;

    public ArrayIntStack(){
        values=new int[10];
        size=0;
    }

    @Override
    public void push(int value) {
        if (size==values.length){
            int[] tmpArr=new int[2*values.length];
            for (int i=0; i<values.length; i++)
                tmpArr[i]=values[i];
            values=tmpArr;
        }
        values[size++]=value;
    }

    @Override
    public int pop() throws Exception {
        if (size<=0){
            throw new Exception("The stack is empty.");
        }
        return values[(size--)-1];
    }

    @Override
    public int getSize() {
        return size;
    }

    @Override
    public void clear() {
        values=new int[10];
        size=0;
    }

    @Override
    public String toString(){
        String list="bottom[";
        for (int i=0; i<size; i++){
            list+=values[i];
            if (i<size-1)
            list+=", ";
        }
        return list+"]top";
    }
}

/////////////////////////////////////////////////////////////////////////////////// Test Classs
public class testClass {
    public static void main(String[] args){
        IntStack myStack=new ArrayIntStack();
        try{
            System.out.println(myStack.pop()+"\n");
        } catch (Exception ex){
            System.out.println(ex.getMessage()+"\n");
        }

        for (int i=0; i<12; i++){
            myStack.push(i);
        }
        System.out.println(myStack);
        System.out.println("Size: "+myStack.getSize()+"\n");

        try {
            System.out.println("Elements removed: "+ myStack.pop()+" "+
                myStack.pop());
        } catch (Exception ex){
            System.out.println(ex.getMessage());
        }
        System.out.println(myStack);
        System.out.println("Size: "+myStack.getSize()+"\n");

        myStack.clear();
        System.out.println(myStack);
        System.out.println("Size: "+myStack.getSize()+"\n");

        for (int i=0; i<22; i++){
            myStack.push(i);
        }
        System.out.println(myStack);
        System.out.println("Size: "+myStack.getSize()+"\n");

    }
}