Stack, queue and graph data structures implemented in C using linked lists.

1 files changed, 50 insertions, 0 deletions

diff --git a/src/stack.c b/src/stack.c
new file mode 100644
index 0000000..7c83c87
--- /dev/null
+++ b/src/stack.c
@@ -0,0 +1,50 @@
+#include "stack.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+Stack *stackAlloc() {
+  Stack *new = malloc(sizeof(Stack));
+  new->first = NULL;
+  new->last = NULL;
+  return new;
+}
+
+void stackAdd(Stack *stack, int item) {
+  struct queueItem *new = malloc(sizeof(struct queueItem));
+  new->item = item;
+  if (stack->first) {
+    // printf("stack->first is NOT NULL");
+    new->next = NULL;
+    new->previous = stack->first;
+    stack->first->next = new;
+    stack->first = new;
+  } else {
+    // printf("stack->first is NULL");
+    new->next = NULL;
+    new->previous = NULL;
+    stack->first = new;
+    stack->last = new;
+  }
+}
+
+int stackPop(Stack *stack) {
+  if (!stack->first) {
+    return -1;
+  }
+  int out = stack->first->item;
+  struct queueItem *toFree = stack->first;
+  stack->first = toFree->previous;
+  free(toFree);
+  return out;
+}
+
+void stackFree(Stack *stack) {
+  struct queueItem *s = stack->first;
+  struct queueItem *t = NULL;
+  while (s) {
+    t = s->previous;
+    free(s);
+    s = t;
+  }
+  free(stack);
+}