Insert a node into a doubly linked list at nth position where n is user defined in data structure in c source code?

Answer 1

# include < stdio.h >

# include < stdlib.h >

struct list

{

char info[20];

struct list *next;

struct list *prev;

};

struct list *new1,*node;

void create(struct list *s,struct list *e)

{

char ch;

node=s;

printf("\nWant to create a node(y/n):");

ch=getche();

while (ch != 'n')

{

node->next = (struct list *) malloc(sizeof(struct list));

node->next->prev= node;

node = node->next;

printf("\n Enter the string value:- ");

gets(node->info);

node->next = e;

e->prev=node;

printf("\n Enter choice--'n' for break: ");

ch = getche();

}

}

void displayL (struct list *s,struct list *e)

{

node = s->next;

while (node!=e)

{

printf(" 0x%x--%s", node,node->info);

node = node->next;

}

printf("\n");

}

void displayR (struct list *e,struct list *s)

{

node = e->prev;

while (node!=s)

{

printf(" 0x%x--%s", node,node->info);

node = node->prev;

}

printf("\n");

}

void insertA(struct list *s)

{

struct list *new1;

int c=1,count;

printf("\nEnter the location:");

scanf("%d",&count);

fflush(stdin);

new1 = (struct list *) malloc(sizeof(struct list));

printf("\nEnter the new value:");

gets(new1->info);

node=s->next;

while(node)

{

if(c==count)

break;

node=node->next;

c++;

}

node->prev->next=new1;

new1->prev=node->prev;

new1->next=node;

node->prev=new1;

}

void main()

{

struct list *start,*end;

clrscr();

start=(struct list *) malloc(sizeof(struct list));

end=(struct list *) malloc(sizeof(struct list));

create(start,end);

printf("\n Created list is as follows(L ->R)\n");

displayL(start,end);

printf("\n Created list displayed from R->L\n");

displayR(end,start);

printf("\nInserting a new location at user specified location\n");

insertA(start);

printf("\n now the listfrom L ->R\n");

displayL(start,end);

printf("\n list from R to L after insertion\n");

displayR(end,start);

getch();

}