Linked list ..help

[varunjpp]

Plz anyone give me code for
1.singly lkedlist
2.doubly linked list
3.circular lnkedlist
4.reverse linked list
using structure in C

at leat explain hw to delete item from middle,add item to middle,serching for item etc

rahul dev datta.

[gobicse]

//Program for linked list

#include
#define TRUE 1

struct node{
int info;
struct node *next;
};

typedef struct node *nodeptr;
nodeptr p,tp;

void startlist() {
int x;
p= getnode();
tp = p;
printf("Enter an item to insert:");
scanf("%d",&x);
p->info = x;
p->next = NULL;
}

void showlist() {
p = tp;
printf("node(p)\t Info\t Next");
while(p!= NULL) {
printf("\n %d \t%d \t%d ",p,p->info,p->next);
p=p->next;
}
putchar('\n');
}

void insafter(noteptr p,int x) {
nodeptr a;
if(p==NULL) {
printf("void insertion");
exit(1);
}
q= getnode();
q->info = x;
q->next = p->next;
p->next = q;
}

nodeptr getnode() {
nodeptr p;
p =(nodeptr) malloc(sizeof(struct node));
return(p);
}

void freenode(nodeptr p) {
free(p);
}

void deleteafter(nodeptr p) {
nodeptr q;
if(p==NULL ::q->next ==NULL) {
printf("void deletion");
exit(1);
}
q=q->next;
p->next = q->next;
freenode(q);
}

void main() {
int choice,i,x;
nodeptr n;
nodeptr getnode();
clrscr();
printf("\n Enter Ur choice 1-> start 2->showlist 3->insert 4->delete 5->end \n");
while (TRUE) {
printf("Enter ur choice");
scanf("%d",&choice);
switch(choice) {
case 1: startlist(); break;
case 2: showlist(); break;
case 3: printf ("Node Insertion: after which node?:");
scanf("%d",&n);
p=n;
printf("Enter the item for insertion:");
scanf("%d",&x);
insafter(p,x);
break;
case 4: printf("Node deletion:After which node?:");
scanf("%d",&n); p=n;
delafter(p);break;
case 5: exit(5);
}
}
}

[gobicse]

Program to illustrate queue using linked list concept:

/*Program to illustrate queue using linked list concept*/
#include /*Link section*/
struct node /*Structure used to represent elements as nodes*/
{
int val;
struct node *next;
}*rear = NULL,*front = NULL,*temp = NULL;

void enqueue(int); /*Function declaration section*/
int dequeue();
void disp();

/*Main Function starts here*/
void main()
{
int opt,item,dele;
/*Loop which processes infinitely and ends when forced by the user*/
do
{
clrscr();
printf("Enter the required option:\n1.Enqueue\n2.Dequeue\n3.View the queue\n4.Exit:");
scanf("%d",&opt); /*Required option is received here*/
switch(opt)
{
case 1:
printf("Enter the value to enqueue:");
scanf("%d",&item);
enqueue(item); /*Element added to the queue */
break;

case 2:
/*Element removed from the queue pointed by the front pointer*/
dele = dequeue();
if(dele == 0)
{
disp();
continue;
}
getch();
break;

case 3:
disp(); /*Displays the queue when called upon*/
break;
}
}while(opt != 4); /*Checks for the entered option*/
}

void enqueue(int item)
{
if(rear == NULL)
{
/*Reserving memory space using malloc*/
rear = (struct node *)malloc(sizeof(struct node));

/*Assigning the first value to the rear pointer*/
rear->val = item;

/*Assigning the next of rear pointer to NULL*/
rear->next = NULL;

/*Assigning the front pointer to the rear pointer*/
front = rear;
}
else
{
/*Reserving memory space using malloc*/
rear->next = (struct node *)malloc(sizeof(struct node));

/*Assigning the value of the next element of rear pointer*/
rear->next->val = item;

/*Assigning the next of next element of rear pointer to NULL*/
rear->next->next = NULL;

/*Moving rear by one node*/
rear = rear->next;
}
}

/*Function used to dequeue an element*/
int dequeue()
{
int dequeued; /*Variable used to store the dequeued element*/
if(front == NULL) /*Checking for the queue to be NULL*/
{
printf("\nQueue is empty\n"); /*Printing the queue is empty*/
return;
}
dequeued = front->val; /*Assigning the dequeued value to a variable*/

/*Printing the dequeued element*/
printf("The dequeued item is %d",front->val);

temp = front; /*Temp initialized to front*/
front = front->next; /*Element is deleted by moving the front pointer*/
free(temp); /*Temp is made free*/
if(front == NULL) /*Checking for the queue to be NULL*/
rear = NULL;
return dequeued; /*Dequeued value is returned here*/
}

/*Function to display the queue elements*/
void disp()
{
if(front == NULL) /*Checking for the queue to be NULL*/
{
printf("The queue is empty");
getch();
return;
}
temp = front; /*Temp initialized to front pointer*/
printf("\nQueue elements are:\n");




/*Loop to display the queue elements*/
while(temp != NULL)
{
printf("%d\n",temp->val);
temp = temp->next; /*Temp is passed to the next node by pointers*/
}
getch();
}


Output:

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:3
The queue is empty

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:1
Enter the value to enqueue:15

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:1
Enter the value to enqueue:69

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:3


Queue elements are:
15
69

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:1
Enter the value to enqueue:39

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:1
Enter the value to enqueue:25

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:1
Enter the value to enqueue:30

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:3

Queue elements are:
15
69
39
25
30



Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:2
The dequeued item is 15

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:2
The dequeued item is 69

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:3

Queue elements are:
39
25
30

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:2
The dequeued item is 39

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:2
The dequeued item is 25


Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:2
The dequeued item is 30

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:2

Queue is empty

Enter the required option:
1.Enqueue
2.Dequeue
3.View the queue
4.Exit:4
-------

[gobicse]

Program to illustrate stack using Linked list concept:

/*Program to illustrate stack using linked list concept*/
#include /*Link section*/
struct node /*Structure used to represent elements as nodes*/
{
int val; /*Element*/
struct node *next; /*Next pointer*/
}*top = NULL,*temp = NULL;
void push(int); /*Function declaration section*/
int pop();
void disp();

/*Main function starts here*/
void main()
{
int opt,item,popped;
/*Loop which processes infinitely and ends when forced by the user*/
do
{
clrscr();
printf("Enter the required option\n1.Push\n2.Pop\n3.View the stack\n4.exit:");
scanf("%d",&opt); /*Option is received here*/
switch(opt)
{
case 1:
printf("Enter the element to push:");
scanf("%d",&item);
push(item); /*Element pushed into the stack*/
break;

case 2:
popped = pop(); /*Element popped out of the stack*/
if(popped == 0)
{
disp();
continue;
}
printf("Popped element = %d",popped);
getch();
break;

case 3:
disp(); /*Used to diplay the stack*/
break;
}
}while(opt != 4);
}

/*Function to push an element into the stack*/
void push(int item)
{
if(top == NULL) /*Condition which checks whether first element*/
{
/*Reserving memory space using malloc*/
top = (struct node *)malloc(sizeof(struct node));

/*Assigning the first element as the entered value*/
top->val = item;

/*Assigning the next pointer to NULL*/
top->next = NULL;
}
else
{
/*Reserving memory space using malloc*/
temp = (struct node *)malloc(sizeof(struct node));

/*Asssigning the entered value into a temporary space*/
temp->val = item;

/*Mapping the next pointer to the previous element*/
temp->next = top;

/*Mapping the top of stack with the current element*/
top = temp;
}
}



int pop()
{
int res;
if(top == NULL) /*Checking for the stack to be empty*/
return(0);
else
{
int pop;
pop = top->val; /*Storing the popped value into a variable*/
temp = top;

/*Manipulating the pointers to remove the element*/
top = top->next;
free(temp); /*Making the temporary space free*/
return pop; /*Returning the value stored to pop out*/
}
}

void disp()
{
if(top == NULL) /*Condition checking for the stack to be empty*/
{
printf("The stack is empty");
getch();
return;
}
temp = top;
printf("The stack elements are:\n");
while(temp != NULL) /*Printing the stack elements*/
{
printf("\n%d",temp->val);

/*Moving the temporary pointer to the next element*/
temp = temp->next;
}
getch();
}




Output:

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:3
The stack is empty

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:1
Enter the element to push:156

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:1
Enter the element to push:185

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:1
Enter the element to push:894

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:1
Enter the element to push:474




Enter the required option
1.Push
2.Pop
3.View the stack
4.exit3
The stack elements are:

474
894
185
156

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:2
Popped element = 474

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:2
Popped element = 894

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:3
The stack elements are:

185
156





Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:2
Popped element = 185

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:2
Popped element = 156

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:2
The stack is empty

Enter the required option
1.Push
2.Pop
3.View the stack
4.exit:4

[vjsreevs]

hi varun,
instead of chkng code given by others its good 2 try 2 develop ur own code understanding the logic behind the qsn ....
yashwant karnetkar - pointers in c book gives basic level explanations of all these concepts ....
try 2 develop ur logic ....

[balanagireddy]

Also try to write the reversing the linked list using the iterative and also recursive approach.