linked list -C++

 A linked list is a data structure that consists of a 

sequence of data records such that in each record there 

is a field that contains a reference (i.e., a link) to 

the next record in the sequence. 

----------------------------------------------------

#include <iostream>
using namespace std;

struct node
{  char name[20];    // Name of up to 20 letters
     int age;          // D.O.B. would be better

     float height;     // In metres
     node *nxt;// Pointer to next node
  };


node *start_ptr = NULL;
node *current;           // Used to move along the list

int option = 0;

void add_node_at_end()
{  node *temp, *temp2;   // Temporary pointers

// Reserve space for new node and fill it with data

     temp = new node;
cout << "Please enter the name of the person: ";

cin >> temp->name;
cout << "Please enter the age of the person : ";
cin >> temp->age;

cout << "Please enter the height of the person : ";
cin >> temp->height;
temp->nxt = NULL;


// Set up link to this node
     if (start_ptr == NULL)
{ start_ptr = temp;

current = start_ptr;
} 
else
{ temp2 = start_ptr;

// We know this is not NULL - list not empty!
         while (temp2->nxt != NULL)
{  temp2 = temp2->nxt;

// Move to next link in chain
           }
temp2->nxt = temp;
}
}

void display_list()
{  node *temp;

temp = start_ptr;
cout << endl;
if (temp == NULL)

cout << "The list is empty!" << endl;
else
{ while (temp != NULL)
{  // Display details for what temp points to

              cout << "Name : " << temp->name << " ";
cout << "Age : " << temp->age << " ";

cout << "Height : " << temp->height;
if (temp == current)

cout << " <-- Current node";
cout << endl;
temp = temp->nxt;

}

cout << "End of list!" << endl;
}
}


void delete_start_node()
{ node *temp;

temp = start_ptr;
start_ptr = start_ptr->nxt;

delete temp;
}

void delete_end_node()
{ node *temp1, *temp2;

if (start_ptr == NULL)
cout << "The list is empty!" << endl;

else
{ temp1 = start_ptr;
if (temp1->nxt == NULL)
{ delete temp1;

start_ptr = NULL;
}
else
{ while (temp1->nxt != NULL)
{ temp2 = temp1;

temp1 = temp1->nxt;
}
delete temp1;
temp2->nxt = NULL;
}
}
}

void move_current_on ()
{ if (current->nxt == NULL)

cout << "You are at the end of the list." << endl;
else
current = current->nxt;
}

void move_current_back ()
{ if (current == start_ptr)

cout << "You are at the start of the list" << endl;
else
{ node *previous;     // Declare the pointer

        previous = start_ptr;

while (previous->nxt != current)
{ previous = previous->nxt;
}

current = previous;
}
}


int main()
{  start_ptr = NULL;

do
{
display_list();
cout << endl;

cout << "Please select an option : " << endl;
cout << "0. Exit the program." << endl;

cout << "1. Add a node to the end of the list." << endl;
cout << "2. Delete the start node from the list." << endl;

cout << "3. Delete the end node from the list." << endl;
cout << "4. Move the current pointer on one node." << endl;

cout << "5. Move the current pointer back one node." << endl;
cout << "6. Display the list. " << endl;

cout << endl << " >> ";
cin >> option;

switch (option)
{
case 1 : add_node_at_end(); break;

case 2 : delete_start_node(); break;
case 3 : delete_end_node(); break;

case 4 : move_current_on(); break;
case 5 : move_current_back(); break;

case 6 : display_list();
}
}
while (option != 0);

return(0);
}