Add header protect thingy in stack.h

1 files changed, 5 insertions, 0 deletions

diff --git a/stack.h b/stack.h
index 72fd1f2..48fea92 100644
--- a/stack.h
+++ b/stack.h
@@ -1 +1,6 @@
+#ifndef STACK_H_
+#define STACK_H_
+
 // TODO: implement a stack
+
+#endif /* STACK_H_ */