add

1 files changed, 16 insertions, 0 deletions

diff --git a/data_structures/chapter_3/stack.h b/data_structures/chapter_3/stack.h
new file mode 100644
index 0000000..f93c467
--- /dev/null
+++ b/data_structures/chapter_3/stack.h
@@ -0,0 +1,16 @@
+#ifndef _STACK_H
+
+struct node;
+typedef struct node *ptr_to_node;
+typedef ptr_to_node stack;
+typedef int elem;
+
+int is_empty(stack s);
+stack create_stack();
+void dispose_stack(stack s);
+void make_empty(stack s);
+void push(elem x, stack s);
+elem top(stack s);
+void pop(stack s);
+
+#endif