Finished LinkedNumberStack

.gitignore

@@ -1 +1,3 @@
 *.dat
+*.class
+/TAGS

LinkedNumberStack.java

@@ -8,7 +8,7 @@ public class LinkedNumberStack implements NumberStack
 
     // check whether the stack is empty
     public boolean isEmpty()
-    {       
+    {
         if (m_top == null)
             return true;
         else
@@ -20,10 +20,10 @@ public class LinkedNumberStack implements NumberStack
     {
         return false;
     }
-    
+
     // return the element at the top of the stack
     public int top()
-    { 
+    {
         if (isEmpty())
             throw new RuntimeException("top attempted on an empty stack");
         else
@@ -33,38 +33,54 @@ public class LinkedNumberStack implements NumberStack
     // push a value onto the stack
     public void push(int v)
     {
-        // TODO: implement this method
+	LNode new_node = new LNode(v);
+        if (isEmpty()) {
+	    m_top = new_node;
+	}
+	else {
+	    new_node.setLink(m_top);
+	    m_top = new_node;
+	}
     }
 
     // remove and return the value at the top of the stack
     public int pop()
-    { 
-        // TODO: implement this method
-		
-        return -1; // replace this statement with your own return
+    {
+	if (isEmpty())
+            throw new RuntimeException("pop attempted on an empty stack");
+        else {
+    	    int top_val = m_top.getInfo();
+	    LNode prev_node = m_top.getLink();
+	    m_top = prev_node;
+	    return top_val;
+	}
     }
 
     // return the number of elements on the stack
     public int size()
-    {       
-        // TODO: implement this method
-		
-        return -1; // replace this statement with your own return
+    {
+	int current_size = 0;
+	LNode current_node = m_top;
+	while (current_node != null) {
+	    current_node = current_node.getLink();
+	    current_size += 1;
+	}
+	return current_size;
     }
 
     // return a string representation of the stack
-    @Override    
+    @Override
     public String toString()
     {
         String stackContent = "";
         LNode current = m_top;
 
         while (current != null)
-        {
-            stackContent += current.getInfo() + " ";
-            current = current.getLink();
-        }
+	    {
+		stackContent += current.getInfo() + " ";
+		current = current.getLink();
+	    }
 
-        return stackContent;    
+        return stackContent;
     }
-}
+}