//a program to perform the following operations on a linked list
#include < stdio.h>
#include < stdlib.h>
//node of the linked list
typedef struct Node{
int data;
struct node *link;
}Node;
//handle of the list. the head pointer in in points towards the first node of the list
typedef struct List{
Node *length;
int length;
}List;
//create an empty list
List* create_list();
//insert a new node at the beginning of the linked list
void insert_beginning(List *list,int data);
//delete the first node having the element "data"
//No operation if there is no such node
void delete_element(List *list,int data);
//display the elements of the linked list separated by spaces on a single line
void disp_list(List *list);
//delete the linked list along with any nodes in it
void delete_list(List *list);
int main()
{
int choice=1;
int element;
List *list=create_list();
while(choice>0 && choice<4)
{
scanf("%d",&choice);// 1:insert an element in the beginning.
// 2:delete a specified element.
// 3:display the list.
switch(choice){
case 1: scanf("%d",&element); //enter the element to be inserted
insert_beginning(list,element);
break;
case 2: scanf("%d",&element); //enter the element to be deleted
delete_element(list,element);
break;
case 3: disp_list(list);
break;
}
}
delete_list(list);
return 0;
}
List* create_list()
{
List *list;
list=(List*)malloc(sizeof(List));
list->head=NULL;
list->length=0;
return list;
}
void insert_beginning(List *list,int data)
{
Node *temp;
temp=(Node*)malloc(sizeof(Node));
temp->data=data;
if(list->head==NULL){
temp->link=NULL;
list->head=temp;
}
else{
temp=list->head;
list->head=temp;
}
list->length++;
temp=NULL;
}
void delete_element(List* list,int data)
{
Node *iter=list->head,*temp=list->head;
int i=1;
while(iter!=NULL)
{
if(temp->data==data){
if(i<2){
list->head=temp->link;
}
else{
iter->link=(Node *)temp->link;
}
free(temp);list->length--;
}
else{
temp=temp->link;i++;
if(i>2){
iter=iter->link;
}
}
}iter=NULL;temp=NULL;
}
void disp_list(List *list)
{
Node *temp;
if(list->head!=NULL){
temp=list->head;
while(temp->link!=NULL){
printf("%d ",temp->data);
temp=temp->link;
}
printf("%d\n",temp->data);
}temp=NULL;
}
void delete_list(List *list)
{
Node *temp=NULL,*iter=list->head;
while(iter!=NULL && iter->link!=NULL){
temp=iter;
iter=iter->link;
free(temp);
}
free(iter);free(list);
}