char-lists-functs.c

/****************
 * @author:lennon mudenda
 * @description::::
 * a c library to provide helper functions when dealing with a linked lists of characters
 * !include stdlib.h always
 * @function list::
 * 1. list creater with known number of elements
 * 2. list creater without known number of elements
 * 3. list elements count
 * 4. add element at positions: start,end,middle:before,middle:after
 * 5. return ith element if exist NULL if not
 * 6. print out list
 * 7. delete list elements at positions:start,end,middle each position has both the logical and physical deletion
 * ***************/
 
 /*********
  * list element declaration
  * 
 */
 typedef struct node
 {
     char c;
     struct node * next;
 } node_c;
 
 /******************
  * @function signatures
 *******************/
 
 void create_list_num(node_c ** h,int num_elem);
 void create_list(node_c ** h);
 int list_num_elem(node_c * h);
 void list_add_start(node_c ** h,node_c ** new_elem);
 void list_add_end(node_c * h,node_c ** new_elem);
 void list_add_mid_before(node_c * h,node_c ** new_elem,node_c ** elem);
 void list_add_mid_after(node_c ** new_elem,node_c ** elem);
 node_c list_ith_elem(node_c * h,int i);
 void print_list(node_c * h);
 void list_delete_start_phy(node_c ** h);
 void list_delete_start_log(node_c ** h,node_c ** x);
 void list_delete_middle_phy(node_c ** h);
 void list_delete_middle_log(node_c ** h,node_c ** x);
 void list_delete_end_phy(node_c ** h);
 void list_delete_end_log(node_c ** h,node_c ** x);

/****************
@function declarations/definitions
*/
 void create_list_num(node_c ** h,int num_elem)
 {
     node_c * pt;
     *h = NULL;
     int i;
     for(i = 0;i < num_elem;i++)
     {
         pt = malloc(sizeof(node_c));
         printf("\n enter a character");
         scanf(" %c",&pt->c);
         pt->next = *h;
         *h = pt;
     }
 }
 void create_list(node_c ** h)
 {  
    char response; 
    node_c * pt;
    *h = NULL;
    printf("do you want to enter another element? y/n: ");
    scanf(" %c",&response);
    while(response == 'y')
    {
        pt = malloc(sizeof(node_c));
        print("\n enter a character ");
        scanf(" %c",&pt->c);
        pt->next = *h;
        *h = pt;
        printf("\n do you want to enter another element? y/n: ");
        scanf(" %c",&response);
    }
 }
 int list_num_elem(node_c * h)
 {
     node_c * pt = h;
     int n = 0;
     while(pt != NULL)
     {
         n += 1;
         pt = pt->next;
     }
     return n;
 }
 void list_add_start(node_c ** h,node_c ** new_elem)
 {
     new_elem->next = h->next;
     *h = new_elem;
 }
 void list_add_end(node_c * h,node_c ** new_elem)
 {
     node_c * pt;
     pt = h;
     new_elem->next = NULL;
     while(pt->next != NULL)
     {
         pt = pt->next;
     }
     pt->next = new_elem;
 }
 void list_add_mid_before(node_c * h,node_c ** new_elem,node_c ** elem)
 {
    node_c * pt;
    pt = h;
    while(pt->next != elem)
    {
        pt = pt->next;
    }
    new_elem->next = elem;
    pt->next = new_elem;
 }
 void list_add_mid_after(node_c ** new_elem,node_c ** elem)
 {
    new_elem->next = elem->next;
    elem->next = new_elem;
 }
 node_c list_ith_elem(node_c * h,int i)
 {
    node_c * pt;
    int co;
    if(list_num_elem(h)<i)
    {
        return NULL;
    }
    else
    {
        pt = h;
        for(co=1;co<i;co++)
        {
            pt = pt->next;
        }
        return *pt;
    }
 }
 void print_list(node_c * h)
 {
     node_c * pt = h;
     while(pt != NULL)
     {
         printf(" %c ",pt->c);
         pt = pt->next;
     }
 }
void list_delete_start_phy(node_c ** h)
{
    node_c * x;
	x = *h;
	*h = h->next;
    free(x);
}
void list_delete_start_log(node_c ** h,node_c ** x)
{
	x = *h;
	*h = h->next;
}
void list_delete_middle_phy(node_c ** h,node ** elem)
{
	node_c * x = h;
	while(x->next != elem)
	{
		x = x->next;
	}
	x->next = elem->next;
	free(elem);
}
void list_delete_middle_log(node_c ** h,node_c * elem)
{
	node_c * x = h;
	while(x->next != elem)
	{
		x = x->next;
	}
	x->next = elem->next;
}
void list_delete_end_phy(node_c ** h)
{
	node_c * x = h;
	while(x->next->next != NULL)
	{
		x = x->next;
	}
	free(x->next);
	x->next = NULL;
}
void list_delete_end_log(node_c ** h,node_c ** elem)
{
	node_c * x = h;
	while(x->next->next != NULL)
	{
		x = x->next;
	}
	elem = x->next;
	x->next = NULL;
}