--- /dev/null
+class StackUnderflowError < RuntimeError
+end
+
+class StackOverflowError < RuntimeError
+end
+
+class Stack
+
+ def initialize
+ @items = []
+ end
+
+ def push object
+ raise StackOverflowError if @items.length == 10
+ @items.push object
+ end
+
+ def pop
+ raise StackUnderflowError if @items.empty?
+ @items.delete @items.last
+ end
+
+ def peek
+ raise StackUnderflowError if @items.empty?
+ @items.last
+ end
+
+ def empty?
+ @items.empty?
+ end
+
+ def full?
+ @items.length == 10
+ end
+
+end