The document describes creating a simple line editor program using a doubly linked list data structure to store each line of text as a separate node. It provides code to implement basic functions for the editor like inserting new lines, deleting lines, appending text, and listing lines. The code sample shows functions to create the first line, add new lines, and read input text to populate the linked list.

1. please help!! C++ Program D@t@ Structur3ss class
please comment code!
Create all!! Code Using Doubly Linked List In this project, you should write a simple line editor.
Keep the entire text on a linked list, one line in a separate node. Stan the program with entering
EDIT file, after which a prompt appeals along with the line number. If the letter I is entered with
a number n following it. then insert the text to be followed before line n. If I is not followed by a
number, then insert the text before the current line. If D is entered with two numbers n1 and m.
one n. or no member following it. then delete lines 11 through 111. line 11. or the current line.
Do the same with the command L. which stands for listing lines. If A is entered, then append the
text to the existing lines. Entry E signifies exit and saving the text in a file. Here is an Example:
Solution
#include
#include
#include
typedef struct Node
{
char character[80];
Node *next, *pre;
}Line;
Line *currentline;
Line *firstline;
Node *head, *tail;
int col;
void createfirstline()
{
Node *p;
p = new Node;
currentline = p;
head = currentline;
tail = currentline;
col = -1;
}
void newline()

2. {
Node *p;
p = new Node;
p -> next = NULL;
p->pre = currentline;
currentline->next = p;
tail = p;
currentline=p;
col = 0;
}
void createnewline()
{
Node *p;
p = new Node;
p -> next = NULL;
if (head == NULL)
{
head = p;
tail = p;
}
else
{
Node *q = tail;
q->next = p;
p->pre = q;
}
tail = p;
currentline = p;
}
void main()
{
cout << "Enter string: ";
char string[30];
cin.getline (string,30);
ifstream instream;

3. instream.open(string);
char reading;
currentline = firstline;
createfirstline();
while(instream.read(&reading,sizeof(reading)))
{
if (reading == ' ')
newline();
else
{
col++;
currentline->character[col] = reading;
}
}
instream.close();
}