program on Link list in c.

here we are understasnd  Link list by a example in which we creat a Link list and insert node  in the list and creat a function to view the list and we also creat a function for delete node from list. This is menu based program.

#include<stdio.h>

struct node

{

int data;

struct node *link;

};

struct node *head=NULL;

//function to create node

struct node *CreatNode()

{

struct node *n;

n=(struct node *) malloc(sizeof(struct node));

return(n);

}

// function for insert node at end

void InsertNodeEnd()

{

struct node *t,*temp;

t=CreatNode();

printf("Enter a value");

scanf("%d",&t->data);

t->link=NULL;

if(head==NULL)

head=t;

else

{

temp=head;

while(temp->link!=NULL)

temp=temp->link;

temp->link=t;

}

}

// function for insert node at starting

void InsertNodestart()

{

struct node *t,*temp;

t=CreatNode();

printf("Enter a value");

scanf("%d",&t->data);

if(head==NULL)

{

head=t;

t->link=NULL;

}

else

{

t->link=head;

head=t;

}

}

// function for delete node from starting

struct node *deleteNodestart()

{

struct node *t;

if(head==NULL)

printf("List is Empty");

else

{

t=head;

head=head->link;

free(t);

}

}

// function for delete node from end

struct node *deleteNodeend()

{

struct node *t,*temp;

if(head==NULL)

printf("List is Empty");

if(head->link==NULL)

{

temp=head;

head=NULL;

free(temp);

}

else

{

t=head;

while(t->link->link!=NULL)

t=t->link;

t->link=NULL;

temp->data=t->link->data;

temp->link=NULL;

free(temp);

}

}

// function for display list

void viewlist()

{

struct node *t;

if(head==NULL)

printf("List is Empty");

else

{

t=head;

while(t!=NULL)

{

printf("%d ",t->data);

t=t->link;

}

}

}

    // driver function

    

void main()

{

int ch;

while(1)

{

clrscr();

printf("Press\n");

printf("1. Add value\n");

printf("2. Delete value\n");

printf("3. view\n");

printf("4. Exit\n");

printf("Enter YOur choice\n");

scanf("%d",&ch);

switch(ch)

{

case 1:

printf("Press\n");

printf("1. at starting\n") ;

printf("2. at end\n");

scanf("%d",&ch);

switch(ch)

{

case 1:

InsertNodestart();

break;

case 2:

InsertNodeEnd();

break;

default:

printf("Invaild key");

}

break;

case 2:

printf("Press\n");

printf("1. From starting\n");

printf("2. From end\n") ;

scanf("%d",&ch);

switch(ch)

{

case 1:

deleteNodestart();

break;

case 2:

deleteNodeend();

break;

default:

printf("Invaild key");

}

break;

case 3:

viewlist();

break;

case 4:

exit(0);

default:

printf("Invaild key");

}

getch();

}

}