1 files changed, 39 insertions, 0 deletions
diff --git a/usth/ICT2.1/labwork/3/stack.c b/usth/ICT2.1/labwork/3/stack.c
new file mode 100644
index 0000000..708fb59
--- /dev/null
+++ b/usth/ICT2.1/labwork/3/stack.c
@@ -0,0 +1,39 @@
+/*
+ * Stack implemented using linked list.
+ * This is free and unencumbered software released into the public domain.
+ */
+
+#include <stdlib.h>
+
+#include "stack.h"
+
+stack *mkstack()
+{
+	stack *s = malloc(sizeof(stack));
+	s->stack = NULL;
+	return s;
+}
+
+int stack_empty(stack *s)
+{
+	return s->stack == NULL;
+}
+
+void stack_push(stack *s, void *item)
+{
+	s->stack = cons(item, s->stack);
+}
+
+void *stack_top(stack *s)
+{
+	return car(s->stack);
+}
+
+void *stack_pop(stack *s)
+{
+	void *first = car(s->stack);
+	construct *rest = cdr(s->stack);
+	free(s->stack);
+	s->stack = rest;
+	return first;
+}