A Linked list is a chain of structs or records called Nodes. Each node has at least two members, one of which points to the next Node in the list and the other holds the data. These are defined as Single Linked Lists because they can only point to the next Node in the list but not to the previous.
// Adding a Node at the Beginning of the List
void addBeg(int num)
{
struct Node *temp;
temp=(struct Node *)malloc(sizeof(struct Node));
temp->Data = num;
if (Head == NULL)
{
//List is Empty
Head=temp;
Head->Next=NULL;
}
else
{
temp->Next=Head;
Head=temp;
}
}
//Adding a Node at the end of the list
void addEnd(int num)
{
struct Node *temp1, *temp2;
temp1=(struct Node *)malloc(sizeof(struct Node));
temp1->Data=num;
// Copying the Head location into another node.
temp2=Head;
if(Head == NULL)
{
// If List is empty we create First Node.
Head=temp1;
Head->Next=NULL;
}
else
{
// Traverse down to end of the list.
while(temp2->Next != NULL)
temp2=temp2->Next;
// Append at the end of the list.
temp1->Next=NULL;
temp2->Next=temp1;
}
}
// Adding a new Node at specified position
void addAt(int num, int loc)
{
int i;
struct Node *temp, *prev_ptr, *cur_ptr;
cur_ptr=Head;
if(loc > (length()+1) || loc <= 0)
{
printf("\nInsertion at given location is not possible\n ");
}
else
{
// If the location is starting of the list
if (loc == 1)
{
addBeg(num);
}
else
{
for(i=1;i<loc;i++)
{
prev_ptr=cur_ptr;
cur_ptr=cur_ptr->Next;
}
temp=(struct Node *)malloc(sizeof(struct Node));
temp->Data=num;
prev_ptr->Next=temp;
temp->Next=cur_ptr;
}
}
}
// Counting number of elements in the List
int length()
{
struct Node *cur_ptr;
int count=0;
cur_ptr=Head;
while(cur_ptr != NULL)
{
cur_ptr=cur_ptr->Next;
count++;
}
return(count);
}
// Deleting a node from List depending upon the data in the node.
int delNodeData(int num)
{
struct Node *prev_ptr, *cur_ptr;
cur_ptr=Head;
while(cur_ptr != NULL)
{
if(cur_ptr->Data == num)
{
if(cur_ptr==Head)
{
Head=cur_ptr->Next;
free(cur_ptr);
return 0;
}
else
{
prev_ptr->Next=cur_ptr->Next;
free(cur_ptr);
return 0;
}
}
else
{
prev_ptr=cur_ptr;
cur_ptr=cur_ptr->Next;
}
}
printf("\nElement %d is not found in the List", num);
return 1;
} If the value to be deleted is the head of the list.
If the value to be deleted is not the head of the list.
Similarly if we want to delete a node based on its location in the list.
// Deleting a node from List depending upon the location in the list.
int delNodeLoc(int loc)
{
struct Node *prev_ptr, *cur_ptr;
int i;
cur_ptr=Head;
if(loc > (length()) || loc <= 0)
{
printf("\nDeletion of Node at given location is not possible\n ");
}
else
{
// If the location is starting of the list
if (loc == 1)
{
Head=cur_ptr->Next;
free(cur_ptr);
return 0;
}
else
{
for(i=1;i<loc;i++)
{
prev_ptr=cur_ptr;
cur_ptr=cur_ptr->Next;
}
prev_ptr->Next=cur_ptr->Next;
free(cur_ptr);
}
}
return 1;
}
// Displaying list contents
void display()
{
struct Node *cur_ptr;
cur_ptr=Head;
if(cur_ptr==NULL)
{
printf("\nList is Empty");
}
else
{
printf("Elements in the List: ");
//traverse the entire linked list
while(cur_ptr!=NULL)
{
printf(" -> %d ",cur_ptr->Data);
cur_ptr=cur_ptr->Next;
}
printf("\n");
}
} Reversing a list.
//Reversesing a Linked List
void reverse()
{
struct Node *prev_ptr, *cur_ptr, *temp;
cur_ptr=Head;
prev_ptr=NULL;
while(cur_ptr != NULL)
{
temp=prev_ptr;
prev_ptr=cur_ptr;
cur_ptr=cur_ptr->Next;
prev_ptr->Next=temp;
}
Head=prev_ptr;
}
