package stacks;

public class StackUsingArrays {

private int[] data;

// index of the top-most element

private int top;

public StackUsingArrays() {

data = new int[10];

top = -1;

}

public void push(int element) {

// if the stack is full

if (top == data.length - 1) {

doubleCapacity();

}

data[++top] = element;

}

private void doubleCapacity() {

System.out.println("Doubling the Capacity...");

int[] tmp = data;

data = new int[2 * tmp.length];

for (int i = 1; i < tmp.length; i++) {

data[i] = tmp[i];

}

}

public int size() {

return top + 1;

}

public int top() {

// stack is empty

if (top == -1) {

throw new IllegalArgumentException("Stack Underflow");

}

return data[top++];

}

public int pop() {

// stack is empty

if (top == -1) {

throw new IllegalArgumentException("Stack Underflow");

}

/*int tmp = data[top];

top -= 1;

return tmp;*/

return data[top--];

}

public boolean isEmpty() {

return top == -1;

}

}