Circular linked list in C++ complete concept

Circular linked list is a type of dynamic list where last node is linked with first node of list.Here complete concept of circular linked list is provided with a C++ program.Let's take a brief overview of working and output of this program.Copy source code from this page and paste it into your editor.Once program have been compiled successfully, it will display the following menu. 

• Enter 1 to create single node:
• Enter 2 to create multiple nodes:
• Enter 3 to delete node from first:
• Enter 4 to delete node from last:
• Enter 5 to create node at first:
• Enter 6 to create node at last:
• Enter 7 to count number of nodes in link list:
• Enter 8 to sum all data in nodes:
• Enter 9 to select and display specific node:
• Enter 10 to create node before any node:
• Enter 11 to delete node before any node:
• Enter 12 to display current link list: 
•  Enter 13 to exit 

A specific function is linked against each menu selection.That will take required input or it will perform required output.For example first menu item is used to create a single node.Once the user pressed one and hit enter, then a single node will be created and user is required to input data into it.Similarly 12 option can be used to display current linked list.There may be some functions that will generate the following output.
                   "This function is not available"
It means function is declared but there is no implementation inside it.So go to that functions and apply implementations by understanding implementations of other functions.This is very easy task that is up  to you.  

#include<iostream>
#include<conio.h>
#include<stdlib.h>
using namespace std;

struct node
{
int data;
node *link;
}*head=NULL;


void create()
{
node *new1=NULL;
node *end=new1;
cout<<"Enter -5 to terminate link list:"<<endl;
while(1)
{
 int info;
cout<<"Enter data: ";
cin>>info;
if(info==-5)
break;
new1=new node;
new1->data=info;
if(head==NULL)
head=new1;
else
end->link=new1;;
end=new1;
end->link=head;


 } 
}

void display()
{
node *p=head;
cout<<"\n\nYour output is:";
while(p->link!=head)
{
cout<<"   "<<p->data;
p=p->link; 
 }
cout<<"  "<<p->data;  
}



void single_node()
{
cout<<"\n\nThis function is not available"; 
}





void delete_first()
{
cout<<"\n\nThis function is not available"; 
}


void delete_last()
{
cout<<"\n\nThis function is not available"; 
}



void  create_first()
{
cout<<"\n\nThis function is not available"; 
}


void create_last()
{
cout<<"\n\nThis function is not available"; 
}


void count_nodes()
{
cout<<"\n\nThis function is not available"; 
}


void sum()
{
cout<<"\n\nThis function is not available"; 
}


void specific_node()
{
cout<<"\n\nThis function is not available"; 
}


void create_before()
{
cout<<"\n\nThis function is not available"; 
}

void delete_before()
{
cout<<"\n\nThis function is not available"; 
}

main()
{
int choice; 
cout<<"\t***Circular link list***"<<endl;
do
{
system("color F"); 
cout<<"Enter 1 to create single node:"<<endl;
cout<<"Enter 2 to create multiple nodes:"<<endl;
cout<<"Enter 3 to delete node from first:"<<endl;
cout<<"Enter 4 to delete node from last:"<<endl;
cout<<"Enter 5 to create node at first:"<<endl;
cout<<"Enter 6 to create node at last:"<<endl;
cout<<"Enter 7 to count number of nodes in link list:"<<endl;
cout<<"Enter 8 to sum all data in nodes:"<<endl;
cout<<"Enter 9 to select and display specific node:"<<endl;
cout<<"Enter 10 to create node before any node:"<<endl;
cout<<"Enter 11 to delete node before any node:"<<endl;
cout<<"Enter 12 to display curent link list:"<<endl;
cout<<"Enter 13 to exit"<<endl;
cin>>choice;

switch(choice)
{
case 1:
single_node(); //creates single node
break;

case 2:
create(); //creates multiple nodes
break;

case 3:
delete_first(); //delete node from first
break;

case 4:
delete_last(); //delete node from last
break;

case 5:
create_first();  //create node at first
break;

case 6:
create_last();  //create node at last
break;

case 7:
count_nodes(); //count number of nodes
break;

case 8:
sum(); //sum all nodes data
break;

case 9:
specific_node(); //display specific node data
break;

case 10:
create_before(); //create node before any node
break;

case 11:
delete_before(); //delete node before any node 
break;

case 12:
display(); //display entire node
break;

case 13://exit path
cout<<"\nPRogram ended";
break;

default:
cout<<"Wrong input"<<endl;
}}while(choice!=13) ;
getch();
 
}

Output of program: