Stack

INFORMATION

Stack is a linear Data Structure that follows a particular order in which the operations are performed. The order may be LIFO(Last In First Out) or FILO(First In Last Out). LIFO implies that the element that is inserted last, comes out first and FILO implies that the element that is inserted first, comes out last.

IMPLEMENTATION

C Language

.h file

typedef struct node_s {
  void *value;
  struct node_s *next;
} node_t, *stack_t;

/* informations */

unsigned int stack_get_size(stack_t stack);
bool stack_is_empty(stack_t stack);

/* Modifications */

bool stack_push(stack_t *stack_ptr, void *elem);
bool stack_pop(stack_t *stack_ptr);
void stack_clear(stack_t *stack_ptr);

/* Access */

void *stack_top(stack_t stack);

.c file

void *stack_top(stack_t stack) { return stack->value; }

unsigned int stack_get_size(stack_t stack) {
  unsigned int len_stack = 0;
  stack_t tmp = stack;

  while (tmp != NULL) {
    len_stack++;
    tmp = tmp->next;
  }

  return len_stack;
}

bool stack_is_empty(stack_t stack) { return (stack == NULL); }

stack_t new_node_stack(void *elem) {
  stack_t node = malloc(sizeof(stack_t));

  if (!node)
    return false;
  node->value = elem;
  node->next = NULL;
  return (node);
}

bool stack_push(stack_t *stack_ptr, void *elem) {
  stack_t node = new_node_stack(elem);

  if (!node)
    return false;
  node->next = *stack_ptr;
  *stack_ptr = node;
  return true;
}

bool stack_pop(stack_t *stack_ptr) {
  stack_t tmp = *stack_ptr;

  if (*stack_ptr == NULL)
    return false;
  *stack_ptr = (*stack_ptr)->next;
  free(tmp);
  return true;
}

void stack_clear(stack_t *stack_ptr) {
  stack_t tmp;

  while ((*stack_ptr) != NULL) {
    tmp = (*stack_ptr)->next;
    free((*stack_ptr));
    *stack_ptr = tmp;
  }
}

void *stack_top(stack_t stack) { return stack->value; }