#include<stdio.h>
#include<conio.h>
/*
you can insert a new item to the end of the Linked List, delete the last
item from the linked list and display all the list items in the linked list. Note that the Linked List
contains integer items. */
/*contains malloc & free functions */
#define NULL 0
struct node{
int info;
struct node *next;
};
typedef struct node nodeptr;
int menu(void);
void insertEnd(nodeptr **, int);/*insert to the end of the list*/
void deleteEnd(nodeptr **, int *);/*delete from the end " " "*/
void displayList(nodeptr *);
nodeptr *getnode(void);
void freenode(nodeptr *);
int main()
{
int choice,x;
nodeptr *List= NULL; /*List points the beginning of the list*/
do{
choice = menu();
switch(choice){
case 1:
printf("Enter new data item:");
scanf("%d",&x);
insertEnd(&List,x);
break;
case 2:
deleteEnd(&List,&x);
printf("The deleted data item is: %d",x);
break;
case 3:
displayList(List);
break;
default:
if(choice == 4)
printf("\nEnd of the Program");
else
printf("\nEnter the choice again");
break;
}
}while(choice !=4);
return 0;
}
/*
Use double pointer if you are changing the
content of the List which is a pointer to the
beginning of the Linked List.
Use single pointer if you are not changing the
content of the List which is a pointer to the
beginning of the Linked List.*/
int menu(void)
{
int c;
printf("\nMain Menu:\n");
printf("1 - Insert an item\n");
printf("2 - Delete an item\n");
printf("3 - Display the Linked List items\n");
printf("4 - Quit\n\n");
scanf("%d",&c);
return c;
}
void insertEnd(nodeptr **plist, int x)
{
nodeptr *p, *q;
p=getnode();
p->info = x;
p->next = NULL;
if(*plist == NULL)
*plist = p;
else{
q = *plist;
while(q->next != NULL)
q = q->next;
q->next = p;
}
}
void deleteEnd(nodeptr **plist, int *px)
{
nodeptr *p,*q;
if(*plist == NULL){
printf("void deletion\n");
return;
}
p = *plist; /*current node*/
q = p->next; /*the node after the current node*/
if(q == NULL){
*px = p->info; /*the data of the deleted element*/
freenode(p);
*plist = NULL;
}
else{
while(q->next != NULL){
p = p->next; /*go to the next node*/
q = p->next;
}
p->next = NULL;
*px = q->info; /*the data of the deleted element*/
freenode(q);
}
}
/*
Use double pointer if you are changing the
content of the plist which is a pointer to the
beginning of the Linked List.
Use double pointer if you are changing the
content of the plist which is a pointer to the
beginning of the Linked List.
*/
void displayList(nodeptr *plist)
{
nodeptr *p;
p = plist; /*current node*/
if(p == NULL){
printf("no node/data is available in the list\n");
return;
}
while(p!= NULL){
printf("%5d", p->info); /*prints the current data*/
p = p->next;
}
}
nodeptr *getnode(void)
{
nodeptr *p;
p = (nodeptr *) malloc(sizeof(nodeptr));
return p;
}
void freenode(nodeptr *p)
{
free(p);
}
