How pointer are used to implement linked list structure

Explain how pointer are used to implement linked list structure.

A linked list is a data structure that is built from structures and pointers. It forms a chain of"nodes" with pointers representing the links of the chain and holding the entire thing together.

A linked list can be represented by a diagram like this one: This linked list has four nodes in it, each with a link to the next node in the series. The last node has a link to the special value NULL, which any pointer (whatever its type) can point to, to show that it is the last link in the chain. There is also another special pointer, called Start (also called head), which points to the first link in the chain so that we can keep track of it.

Defining the data structure for a linked list

The key part of a linked list is a structure, which holds the data for each node (the name, address, age or whatever for the items in the list), and, most importantly, a pointer to the next node. Here we have given the structure of a typical node:

struct node

{ char name[20]; // Name of up to 20 letters int age

float height; // In metres

node *nxt;// Pointer to next node };

struct node *start_ptr = NULL;

The important part of the structure is the line before the closing curly brackets. This gives a pointer to the next node in the list. This is the only case in C++ where you are allowed to refer to

a data type (in this case node) before you have even finished defining it!

We have also declared a pointer called start_ptr that will permanently point to the start of the list. To start with, there are no nodes in the list, which is why start_ptr is set to NULL.