Struct |
  
|
Struct |
|
A struct is a group of data elements grouped under one name.
These data elements can have different types and different lengths.
Data structures can be declared in SQC using the following syntax:
struct struct_name
{
type1 name1;
type2 name2;
type3 name3;
...
} object;
struct struct_name object_name;
Example:
typedef struct
{
struct node_t *left;
struct node_t *right;
int data;
}node_t;
node_t* get_new_node()
{
node_t *nd = malloc(sizeof(node_t));
if(nd == 0)
{
printf("Allocation failed \n");
return -1;
}
return nd;
}
node_t* new_list()
{
node_t *new_ = get_new_node();
new_->data = -1;
new_->right = new_;
new_->left = new_;
return new_;
}
node_t* insert_right(node_t *list, int data)
{
node_t *new_ = get_new_node();
new_->data = data;
new_->left = list;
new_->right = list->right;
list->right = new_;
new_->right->left = new_;
return new_;
}
node_t* delete_(node_t* list)
{
list->right->left = list->left;
list->left->right = list->right;
return list->left;
}
node_t* restore(node_t *list)
{
list->right->left = list;
list->left->right = list;
return list;
}
void print_all(node_t* list)
{
node_t *head = list;
node_t *current = list;
printf("%d ", head->data);
current = current->right;
while (head != current)
{
printf("%d ", current->data);
current = current->right;
}
}
int main(void)
{
node_t
*head = new_list(),
*current = head;
for (int i = 1; i <= 10; i++ )
{
current = insert_right(current, i);
}
printf("\nList from head:\n");
print_all(head);
printf("\nList from current:\n");
print_all(current);
current = current->left;
current = delete_(current);
printf("\nList after delete:\n");
print_all(head);
current = delete_(head);
printf("\nList after head delete:\n");
print_all(current);
head = restore(head);
printf("\nList after head restore:\n");
print_all(head);
return 0;
}
Output:
List from head:
-1 1 2 3 4 5 6 7 8 9 10
List from current:
10 -1 1 2 3 4 5 6 7 8 9
List after delete:
-1 1 2 3 4 5 6 7 8 10
List after head delete:
10 1 2 3 4 5 6 7 8
List after head restore:
-1 1 2 3 4 5 6 7 8 10