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#include <iostream>
#include <ncurses.h>
#include <unistd.h>
#include <cctype>
using namespace std;
struct Node {
char data;
Node* next;
Node* prev;
};
class Line {
private:
Node* head;
Node* tail;
Node* cursor;
public:
// start with a Line that only contains a node of ' '
Line() {
Node* start = new Node; //start node
head = start; //head, tail, cursor are the same place
tail = start;
cursor = start;
start->data = ' '; //making it empty
start->prev = NULL; //setting nulls on both ends
start->next = NULL;
}
// same as above, but load str into the list also
Line(string str) {
Node* first = new Node; //making the first node
head = first; //head, tail, cursor are all at first
tail = first;
cursor = first;
first->data = ' '; //making first empty
first->prev = NULL; //setting nulls on both ends
first->next = NULL;
for(int i=0; i<= str.length(); i++) { //using a for loop on the string
if(i == 1 ) {
cursor->prev = head;
head->prev = NULL;
}
add(str[i]); //add function to add new nodes
}
}
// add the new node before the cursor
void add(char key) {
Node* findFront = cursor; //node pointer to position head
Node* findBack = cursor; //node pointer to position tail
Node* addMe = new Node; //new node to add
addMe->data = key; //key is data in addMe node
addMe->next = NULL;
addMe->prev = NULL;
if(!cursor->prev) { //if the list is empty
addMe->prev = NULL; //the added node's prev is null
addMe->next = cursor; //addMe next is the cursor
cursor->prev = addMe; //cursor prev = addM
head = addMe;
}
if(cursor->prev) { //if the list is not empty
cursor->prev->next = addMe; //the node behind the cursor not points at addMe
addMe->next = cursor; //addMe next is now the cursor
addMe->prev = cursor->prev; //addMe prev is the node that was behind the cursor
cursor->prev = addMe; //cursor prev is now addMe
}
/* //this is probably overkill
while(findFront->prev != NULL) { //while findFront exits
findFront = findFront->prev; //traverse to the beginning of list
}
head = findFront; //head is the first node
delete findFront; //delete temp node pointer
while(findBack) { //while findBack exists
findBack = findBack->next; //traverse to end of list
}
tail = findBack; //tail is end of the list
*/// delete findBack; //delete temp node pointer
}
// remove the node before the cursor
void remove() {
while(cursor->prev) { //while there is something to delete
Node* toDelete = cursor->prev; //creating temp node to delete
if (!cursor->prev->prev) { //if you are deleting the only thing in the list
cursor->prev = NULL; // cursor prev is now null
delete toDelete; //deleting offending node
}
if (cursor->prev->prev) { //if you are deleting a thing in the list
cursor->prev->prev->next = cursor; //the node behind the node behind cursor now points at cursor
cursor->prev = cursor->prev->prev; //cursor now points at the node two back from cursor
delete toDelete; //delete the offendind node
}
}
}
// print the line
void print() {
if(head == NULL) {
cout << "There is nothing here! This should never happen!" << endl;
}
Node* temp = head; //creating temp node for iteration set to head
int counter = 0; //counter so ncurses can highlight the cursor
while(temp != NULL) { //while the list exists
if(temp == cursor) { //if temp and cursor are the same
attron(COLOR_PAIR(1)); //invert colors
mvaddch(5,counter,temp->data); //add color effect
// cout << (*temp).data;
attroff(COLOR_PAIR(1)); //return colors
} else {
cout << temp->data; //otherwise cout data
temp = temp->next; //iterate through
counter++; //increase counter
}
}
// recall to print the cursor, that to turn use color
// the code looks like this:
// attron(COLOR_PAIR(1));
// mvaddch(row, col, char);
// attroff(COLOR_PAIR(1));
}
// move the cursor left or right
void moveCursor(char input) {
if(input == 'l' && cursor->prev != NULL ) { //if left arrow key is pressed and there is a node before the cursor
cursor = cursor->prev; //move the cursor
}
if(input == 'r' && cursor->next != NULL ) { //if right arrow is pressed and there is a node after the cursor
cursor = cursor->next; //move the cursor
}
}
// destructor deletes all nodes in the list
~Line() {
Node* check = head; //temp nodes for distruction
Node* destroy = head;
while(!tail) { //while not at the end
check = check->next; //iterate check
delete destroy; //destroy destroy
destroy = check; //set destroy to check
}
if(tail){ //at the end
delete destroy; //delete temp nodes
delete check;
}
}
};
int main() {
// set up ncurses stuff
initscr();
keypad(stdscr, TRUE); // lets the arrow keys work
start_color();
init_pair(1, COLOR_BLACK, COLOR_WHITE);
noecho(); // makes the keystroke NOT be printed
nodelay(stdscr, TRUE); // makes getch NOT WAIT for input
curs_set(0); // turn off the regular cursor
// declare line
Line l("start with this text"); // construct the starting line
int input = 'a';
// modification loop
while(input != 27) { // 27 is the escape key
// get input
input = getch();
// put the input into the line or move the cursor
if(isalpha(input) || input == ' ') {
l.add(input);
} else if(input == KEY_LEFT) {
l.moveCursor('l');
} else if(input == KEY_RIGHT) {
l.moveCursor('r');
} else if(input == KEY_BACKSPACE) { // backspace
l.remove();
}
// display line with cursor and pause
l.print();
refresh();
usleep(10000);
}
// exit
endwin();
return 0;
}
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