Java Integer Stack Class
// Implements a stack of integers. class IntStack { // Stack node type. private class StackNode { StackNode(int d, StackNode n) { data = d; next = n; } public int data; public StackNode next; } // Head of the stack private StackNode head = null; // Push onto the stack. public void push(int i) { head = new StackNode(i, head); } // Remove from the stack. public int pop() { if (head != null) { // Get the head and remove it. int retval = head.data; head = head.next; // Return the value. return retval; } else return 0; } // Find out what's on the top. public int top() { if(head == null) return 0; else return head.data; } // So, are we empty yet? public boolean isEmpty() { return head == null; } // Remove all memory from the stack. public void clear() { head = null; } // Technically, we should probably overload compareTo and clone to // to just throw, which is the closest Java equivalent to forbidding // comparing and copying. But it's not quite the same in the Java // context, so not as useful, and I doubt a Java programmer would find it // worthwhile. }