OK,
I'm trying to write a program that uses a circular linked list. I have been playing around with a linked list program all day, and kinda understand it. Here it is, and yes it does compile.
#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";}
// else if (temp == NULL){
// cout << " <-- Last Node" << endl;}
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;
}
}
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 << 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();
}
}
while (option != 0);
return 0;
}My problem is that, I can't find any good resources on circular linked lists. I know that the last node in a circular linked list points
to the first node, but I can't figure out how to do this. Should I create another pointer in the struct??
My program is supposed to build a linked list of cards, and perform operations such as insert, delete, traverse.
Also, what is the true definition of traverse???
My directions say that a "card" can be inserted anywhere into the stack, and be traversed back to the "home card".
If anybody can get me pointed in the right direction, it would be greatly appreciated.
Again, the code above is just a normal linked list. If I am traversing any thing in the program, let me know so I can understand what that means more clearly.
John
