does potts now, no external libraries

1 files changed, 41 insertions, 0 deletions

diff --git a/lib/stack.c b/lib/stack.c
new file mode 100644
index 0000000..9fde1e6
--- /dev/null
+++ b/lib/stack.c
@@ -0,0 +1,41 @@
+
+#include "stack.h"
+
+void stack_push(ll_t **q, v_t x) {
+  ll_t *nq = malloc(sizeof(ll_t));
+  nq->x = x;
+  nq->next = *q;
+
+  *q = nq;
+}
+
+void stack_push_d(dll_t **q, double x) {
+  dll_t *nq = malloc(sizeof(dll_t));
+  nq->x = x;
+  nq->next = *q;
+
+  *q = nq;
+}
+
+v_t stack_pop(ll_t **q) {
+  ll_t *old_q = *q;
+
+  *q = old_q->next;
+  v_t x = old_q->x;
+
+  free(old_q);
+
+  return x;
+}
+
+double stack_pop_d(dll_t **q) {
+  dll_t *old_q = *q;
+
+  *q = old_q->next;
+  double x = old_q->x;
+
+  free(old_q);
+
+  return x;
+}
+