Thread: nodes

Nodes are often used to store data.

Generaly you use a node in a linked list. Each node contains data and a pointer to the next node. Think of a node as a container that holds your data and has a label that has the location for the next node.

A node is something that connects everything together. A linked list can have nodes that are connected together.

For example:

Code:

struct Node {
   int data;
   Node* nextNode;
};

Observe that the node contains data and a pointer to the next node.
Sometimes you will see a binary tree that has a node with two pointers, one to the left and one to the right. In essence all the data is still connected, but in a different manner.

Some example code that uses nodes can be as simple as:

Code:

#include <iostream>
using namespace std;

struct node {
   int data;
   node* next;
};

int main () {
   node one;   //our first data container
   node two;   //our second data container that will be pointed to by one

   one.data = 1;   //our int will be one obviously, but data can be anything you want it to be
   one.next = &two;   //we will have one point to two

   two.data = 2;
   two.next = NULL;   //two is the last item linked so it doesnt need to point anywhere

   //now to access the data we can simply do

   node* temp = &one;
   while (temp != NULL) {
      cout << temp->data << endl;
      temp = temp->next;
   }
   
   cin.get();
   return 0;
}

In conclusion, Nodes are used to store data in a "linked" manner. Each node contains data and a pointer to the next node.

Code:

Node 1        Node 2        Node 3
+------+      +------+      +------+
| data |  ->  | data |  ->  | data |
+------+      +------+      +------+

// -> == pointer
// data can be whatever you want, any type
// nodes can point to any node, it doesnt have to be in order

Just to make sure its clear...

A Node holds data, just like an array can hold data.

In an array you have random access, meaning you can simply gain access to a value at any random location on the array.

So if I had an array:

Code:

int array[3] = {0, 1, 5};

Then I can randomly access any number:

Code:

cout << array[2] << endl;
cout << array[0] << endl;
cout << array[1] << endl;

The way I access it doesnt have to be incremental. But if I were to use nodes, than I have to start at a node and can only go to the next node and so forth.

Code:

// pseudocode:
Make 3 nodes connected together with data in each
Make a temp node pointer
   point temp to the first node
// to get to the second node:
change temp to temp->next so that temp is positioned at the 2nd node
now output the data from temp

if you need more code as an example, take a look at the code I submitted for ilovevector's contest #3. the code is in one of ilovevector's posts further down the page (it may even be on a second/third page for you - I have it set to board max posts/page)

A graph G is a set of vertex (nodes) v connected by edges (links) e. Thus G=(v , e).

Vertex (Node). A node v is a terminal point or an intersection point of a graph. It is the abstraction of a location such as a city, an administrative division, a road intersection or a transport terminal (stations, terminuses, harbors and airports).

Edge (Link). An edge e is a link between two nodes. The link (i , j) is of initial extremity i and of terminal extremity j. A link is the abstraction of a transport infrastructure supporting movements between nodes. It has a direction that is commonly represented as an arrow. When an arrow is not used, it is assumed the link is bi-directional.

source: http://people.hofstra.edu/geotrans/e...n/ch2m1en.html