Data Structure

### Insertion At Location in linear linked list

#### Algorithm

```InsertAtlocDll(info,next,start,end,loc,size)
1.set nloc = loc-1 , n=1
2.create a new node and address in assigned to ptr.
3.check[overflow] if(ptr=NULL)
write:overflow and exit
4.set Info[ptr]=item;
5.if(start=NULL)
set next[ptr] = NULL
set start = ptr
else if(nloc<=size)
repeat steps a and b while(n != nloc)

a.	loc = next[loc]
b.	n = n+1
[end while]
next[ptr] = next[loc]
next[loc] = ptr
else
set last = start;
repeat step (a) while(next[last]!= NULL)
a. last=next[last]
[end while]
last->next = ptr ;
[end if]
6.Exit.
```

### Fuction For Insert at Location

```void insertAtloc(node **start,int item , int i,int k )
{
node *ptr,*loc,*last;
int n=1 ;
i=i-1;
ptr=(node*)malloc(sizeof(node));
ptr->info=item;
loc = *start ;
if(*start==NULL)
{
ptr->next = NULL ;
*start = ptr ;
}
else if(i<=k)
{   while(n != i)
{
loc=loc->next;
n++;
}
ptr->next = loc->next ;
loc->next = ptr ;

}
else
{
last = *start;
while(last->next != NULL)
{last=last->next;
}
last->next = ptr ;
}
}
```

### C programe for insertion at location in linear linked list

```#include<stdio.h>
#include<malloc.h>
#include<conio.h>
typedef struct Node
{
int info ;
struct Node *next;
}node;
void createsig(node**,int);
void insertAtloc(node **,int,int,int);
void display(node *);

void main()
{
int ch, item, pos,loc,i;
node *start ;
start = NULL;
clrscr();
printf("Enter number of node: ");
scanf("%d",&i);
createsig(&start,i);
printf("\nThe list is : ");
display(start);
printf("\nEnter the loc : ");
scanf("%d",&loc);
printf("\n\nEnter the item to be inserted at loc : ");
scanf("%d",&item);
insertAtloc(&start,item,loc,i);
printf("\nNow the list is : ");
display(start);
getch();
}
void createsig(node **start,int i)
{       int item ,k=1;
while(i)
{ node *ptr,*last;
printf("\nEnter the info for node %d : ",k);
scanf("%d",&item);
ptr=(node*)malloc(sizeof(node));
ptr->info=item;
ptr->next=NULL;
if(*start==NULL)
{
*start = ptr ;
}
else
{	last = *start;
while(last->next != NULL)
{last=last->next;
}
last->next = ptr ;
}
i--;
k++;
}
}
void insertAtloc(node **start,int item , int i,int k )
{
node *ptr,*loc,*last;
int n=1 ;
i=i-1;
ptr=(node*)malloc(sizeof(node));
ptr->info=item;
loc = *start ;
if(*start==NULL)
{
ptr->next = NULL ;
*start = ptr ;
}
else if(i<=k)
{   while(n != i)
{
loc=loc->next;
n++;
}
ptr->next = loc->next ;
loc->next = ptr ;

}
else
{
last = *start;
while(last->next != NULL)
{last=last->next;
}
last->next = ptr ;
}
}

void display(node *start)
{
while(start !=NULL)
{ printf("\t %d",start->info);
start = start->next;
}
}

```

### Output

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