JAVA Write a simple line editor. Keep the entire text in an ArrayList object, on
ID: 3734245 • Letter: J
Question
JAVA
Write a simple line editor. Keep the entire text in an ArrayList object, one line in a separate index position. Start the program with entering EDIT file, after which a prompt appears along with the line number. If the letter I is entered with a number n following it, then insert the text to be followed on line n. IfI is not followed by a number, then insert the text on the current line. If D is entered with two numbers n and m, one n, or no number following it, then delete lines n through m, line n, 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: EDIT testfile 1> The first line 3> And another line 4> I 3 3>The second line > One more line 5> L 1> The first line 2> 3> The second line > One more line 5> And another line /This is now line 5, not 3; 5> D 2 4> L 1> The first line 2> The second line 3> One more line 4> And another line 5> E // line 5, since L was issued from line 5; // line 4, since one line was deleted; //this and the following line was deleted: // now have new number;Explanation / Answer
Answer :
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class TextEditor {
public static List<String> lines = new ArrayList<String>();
public static void main(String[] args) throws IOException
{
Scanner s = new Scanner(System.in);
System.out.print("Input file: ");
String fileName = s.nextLine();
BufferedReader br = new BufferedReader(new FileReader(new File(fileName)));
String str="";
int count=0;
while((str=br.readLine())!=null)
{
lines.add(count, str);
System.out.println((++count) + "> "+ str);
}
String text="";
String command = "";
System.out.print((++count)+"> ");
command=s.nextLine();
String commandArr[];
int flag;
while(!command.equals("E"))
{
flag=0;
commandArr = command.split("\s");
if(commandArr[0].equals("I")) //Insertion
{
while(true)
{
if(commandArr.length==1&&flag!=2)
{
System.out.print((count)+"> ");
text = s.nextLine();
insertLine(text,count-1);
}
else if(commandArr.length==2&&flag!=2)
{
System.out.print((commandArr[1])+"> ");
count=Integer.parseInt(commandArr[1]);
text = s.nextLine();
insertLine(text,Integer.parseInt(commandArr[1])-1);
}
else
insertLine(text,count-1);
System.out.print((++count)+"> ");
command=s.nextLine();
commandArr = command.split("\s");
if(commandArr[0].equals("I")||commandArr[0].equals("L")||commandArr[0].equals("D")||commandArr[0].equals("E"))
{
flag=1;
break;
}
else
{
flag=2;
text=command;
}
}
}
else if(commandArr[0].equals("L")) //Listing
{
printList();
}
else if(commandArr[0].equals("D")) //Deletion
{
if(commandArr.length==1)
{
deleteLine(count-1,count-1);
}
else if(commandArr.length==2)
{
deleteLine(Integer.parseInt(commandArr[1])-1,Integer.parseInt(commandArr[1])-1);
}
else if(commandArr.length==3)
{
deleteLine(Integer.parseInt(commandArr[1])-1,Integer.parseInt(commandArr[2])-1);
}
count=lines.size();
}
if(flag!=1)
{
System.out.print((count++)+"> ");
command = s.nextLine();
}
}
}
public static void insertLine(String text,int count)
{
lines.add(count,text);
}
public static void deleteLine(int start,int end)
{
for(int i=start;i<=end;i++)
lines.remove(i);
}
public static void printList()
{
for(int i=0;i<lines.size();i++)
System.out.println((i+1)+"> "+lines.get(i));
}
}
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