add link to the new revision of my book, organize the folders to add further examples

src/examples_book/adt/stacks/stack.py

@@ -0,0 +1,40 @@
+#!/usr/bin/python3
+# mari von steinkirch @2013
+# steinkirch at gmail
+
+class Stack(object):
+    ''' define the stack class '''
+    def __init__(self):
+        self.items = []
+
+    def isEmpty(self):
+        return self.items == []
+
+    def push(self, items):
+        self.items.append(items)
+
+    def pop(self):
+        return self.items.pop()
+        
+    def peek(self):
+        return self.items[-1]
+
+    def size(self):
+        return len(self.items)
+
+   
+        
+
+def main():
+    stack = Stack()
+    stack.push(1)
+    stack.push(2)
+    stack.push(3)
+    print(stack.size())    
+    print(stack.peek())   
+    print(stack.pop())  
+    print(stack.peek())    
+
+
+if __name__ == '__main__':
+    main()