Non-destructive stack#reverse.

lib/stack.c

@@ -95,17 +95,17 @@ struct stack *pop(struct stack **stack) {
   return(popped_entry);
 }
 
-struct stack *reverse(struct stack **stack) {
+struct stack *reverse(struct stack *stack) {
-  if (length(*stack) > 1) {
+  if (length(stack) > 1) {
     struct stack *tmp_stack;
 
     allocate_stack(&tmp_stack);
     initialize_stack(tmp_stack);
-    while (!empty(*stack)) {
+    while (!empty(stack)) {
-      push(&tmp_stack, pop((stack))->card);
+      push(&tmp_stack, pop((&stack))->card);
     }
     return(tmp_stack);
   } else {
-    return(*stack);
+    return(stack);
   }
 }

lib/stack.h

@@ -17,6 +17,6 @@ bool empty(struct stack *);
 int length(struct stack *);
 void push(struct stack **, struct card *);
 struct stack *pop(struct stack **);
-struct stack *reverse(struct stack **);
+struct stack *reverse(struct stack *);
 
 #endif

test/stack_test.c

@@ -222,7 +222,7 @@ void test_reverse_on_empty_stack() {
   allocate_stack(&stack);
   initialize_stack(stack);
   old_stack = stack;
-  reversed_stack = reverse(&stack);
+  reversed_stack = reverse(stack);
 
   assert(reversed_stack == old_stack);
 
@@ -241,7 +241,7 @@ void test_reverse_on_stack_with_one_element() {
   initialize_stack(stack);
   push(&stack, card);
   old_stack = stack;
-  reversed_stack = reverse(&stack);
+  reversed_stack = reverse(stack);
 
   assert(reversed_stack == old_stack);
 
@@ -261,7 +261,7 @@ void test_reverse_on_stack_with_more_than_one_element() {
     push(&stack, card[i]);
   }
   old_stack = duplicate_stack(stack);
-  reversed_stack = reverse(&stack);
+  reversed_stack = reverse(stack);
 
   allocate_stack(&unreversed_stack);
   initialize_stack(unreversed_stack);
@@ -275,6 +275,26 @@ void test_reverse_on_stack_with_more_than_one_element() {
   free_stack(stack);
 }
 
+void test_reverse_should_not_change_stack() {
+  struct stack *stack, *old_stack;
+  struct card *card[3];
+
+  allocate_stack(&stack);
+  initialize_stack(stack);
+  for (int i = 0; i < 3; i++) {
+    allocate_card(&card[i]);
+    initialize_card(card[i]);
+    set_card(card[i], TWO + i, DIAMONDS + i, EXPOSED, 0, 0);
+    push(&stack, card[i]);
+  }
+  old_stack = stack;
+  reverse(stack);
+
+  assert(stack == old_stack);
+
+  free_stack(stack);
+}
+
 void test_stack() {
   test_initialize_stack();
 
@@ -294,6 +314,7 @@ void test_stack() {
   test_reverse_on_empty_stack();
   test_reverse_on_stack_with_one_element();
   test_reverse_on_stack_with_more_than_one_element();
+  test_reverse_should_not_change_stack();
 
   return;
 }