1. Write a definition for a Node class that holds a number.
2. Write a method that sums up all of the numbers held within a linked list and returns the sum
14-2

class Node
{ public int Data; public Node Next;
}
14-3

int Sum(Node current)
{ if (current == null) return 0; else return current.Data +
Sum(current.Next);
}
int Sum(Node current)
{ int s = 0; while (current != null)
{ s += current.Data; current = current.Next;
} return s;
}
14-4

• Implement a first-in-last-out behavior
• Push() to add an element
• Pop() to remove an element
• Add and remove from the same side of the internal data structure
• Easiest to add/remove from the front if implemented as a linked list internally
• Peek() returns the top element without popping it from the stack
14-5

• Which data structure would you pick to implement a Stack? Why?
14-6

• Implement a first-in-first-out behavior
• Enqueue() to add an element
• Dequeue() to remove an element
• Add and remove from the opposite sides of the internal data structure
• If we maintain a list-tail reference, then we can add to the end and remove from the front, each having constant - O(1) - time
14-7

• Which data structure would you pick to implement a Queue? Why?
14-8