commands.txt

Read input.txt
Delete Microsoft
Print backward
Print forward

editor.cpp

#include <iostream>
#include <string>
#include <fstream>
using namespace std; 

struct wordNode{
	string word;
	wordNode *nextLink;
	wordNode *prevLink;
};

void performPrint(wordNode *w, string s2);

void performDelete(wordNode *f, wordNode *l, string s1);

void performInsert(wordNode *f, wordNode *l, string s1, string s2);

void main(){//int arc, char *argv[]){

	ifstream comFile;
	string command;
	string pass1;
	string pass2;
	wordNode *first, *last, *newNode;
	string fromFile;
	bool firstComm = true;
	
	comFile.open("commands.txt");//argv[1]);

	if(comFile.fail())
		exit(1);

	while(!comFile.eof()){
		comFile>>command;
		comFile>>pass1;

		if(command == "Read" && firstComm){
			ifstream mainFile;
			mainFile.open(pass1);

			if (mainFile.fail()){
				cout << "Failed to open text file.\n";
				exit(1);
			}
			
			first = NULL;
			last = NULL;

			while(!mainFile.eof()){
				mainFile>>fromFile;
				newNode = new wordNode;
				newNode->word = fromFile; //new word from file is assigned as the word of the new node
				newNode->nextLink = NULL; //assigns NULL to the new nodes link
				newNode->prevLink = NULL;
	
				if (first == NULL){ //if list is empty, the new node is the first && the last entry
					first = newNode;
					first->prevLink = NULL;
					last = newNode;
				}
				else{ //if list is not empty, assign the new node as the last entry and the last->link as the link of the new node aka NULL
					newNode->prevLink = last;
					last->nextLink = newNode;
					last = newNode;				
				}
			}
			firstComm = false;
		}
		else{
			if(command =="Print"){
				if(pass1 == "backward")
					performPrint(last, pass1);
				else
					performPrint(first, pass1);					
			}
			else if(command =="Delete"){
				performDelete(first, last, pass1);
			}
			else if(command =="Insert"){
				comFile>>pass2;
				performInsert(first, last, pass1, pass2);
			}
		}
	}

	comFile.close();

	system("pause");
}

void performPrint(wordNode *position, string pass1){	
	if(pass1 == "forward"){
		wordNode *current;
		current = position;
		while(current != NULL){
			cout << current->word << endl;

			current = current->nextLink;
		}
	}
	else if(pass1 == "backward"){
		wordNode *current;
		current = position;
		while(current != NULL){
			cout << current->word << endl;

			current = current->prevLink;
		}
	}
}
//end of Print command

void performDelete(wordNode *head, wordNode *tail, string pass1){ //deletes a word as well as the occupied memory
	bool found = false;

	wordNode *current;
	current = new wordNode;
	if(head == NULL && tail == NULL) //checks for empty list
		cout<<"This list is empty. Nothing to delete.\n";
	else if(head->word == pass1){ //checks to see if the first word is the target word
		current = head;
		head = head->nextLink;
		head->prevLink = NULL;
		current->nextLink = NULL;
		
		delete current;
	}
	/*else if(head != NULL){ //if head is not empty, change the prevLink to NULL
		head->prevLink = NULL;
		
		current->nextLink = NULL;
		current->prevLink = NULL;

		delete current;
	}
	else if(current != NULL && !found){
	}*/
} //end of Delete command


void performInsert(wordNode *head, wordNode *tail, string pass1, string pass2){ //insert pass1 after pass2
/*	wordNode *current, *newNode;
	newNode = new wordNode;
	newNode->word = pass1;
	newNode->nextLink = NULL;
	newNode->prevLink = NULL;
	bool found = false;
	current = head;

	while(current != NULL && !found){
		if(current->word == pass2){
			found = true;
		}
		else{
			current = current->nextLink;
		}
	}

	if(current == head){
		newNode->nextLink = head->nextLink;
		head = newNode;
	}
	else{
		if(current != NULL){
			newNode->prevLink = current;
			newNode->nextLink = current->nextLink;
			current->nextLink->prevLink = newNode;
			current->nextLink = newNode;
		}
	}
*/}

    

input.txt

Microsoft has many many products,
such as Windows