Question

Java Programming Project 6: File I/O

Purpose: To practice reading from as well as writing to text files with the help of Scanner class methods, and PrintStream class methods. You will also learn to implement some simple Exception Handling.

Carefully examine and follow ALL the program specifications.

Take a look at the PPT slides for Chapter 7 File I/O for examples that will help with this program.

Hotel Expense Recording Keeping:

A hotel bookkeeper enters client hotel expenses in a text file. Each line contains the following, separated by semicolons: client name, service sold (i.e., Dinner, Conference, Lodging, etc.), the sales amount, and the date.

1. Your program should first query the user for the name of the input file and read it in. Display an error if the input file is not found (does not exist).
2. Then the program should read the file (line by line), keep a running tally of the total amount for each kind of service,
3. Finally display the total amount for each service category. In addition to displaying totals on the screen, the totals should also be written to an output file.
4. Additionally your program should include some exception handling. An Exception that should be checked (and handled) would be a FileNotFoundException.

Attached (and below) is an example input file that your program will be tested with, so you will need to make sure that you program will run correctly using this file. Since this may be your first experience reading from an input file, you will likely find it easiest if you store the input file in the same folder with your Java program file so that they can easily communicate with one another. The easiest way to store this file is as a plain text file in Notepad (do not use MS word or any other sophisticated word processor or you will be processing embedded text commands, which is not at all recommended). Here is what the input file looks like:

Jason Inouye;Conference;250.00;11/10/2016

Jason Inouye;Lodging;78.95;11/10/2016

Mary Ryan;Dinner;16.95;11/10/2016

Mark Twain;Dinner;25.50;11/10/2016

Mark Twain;Spa;50.00;11/10/2016

Steven Hawking;Conference;250.00;11/10/2016

Steven Hawking;Room Service;45.00;11/11/2016

Steven Hawking;Lodging;78.95;11/11/2016

Ayrton Senna;Room Service;23.20;11/10/2016

Ayton Senna;Dinner;22.50;11/10/2016

Ayton Senna;Lodging;78.95;11/10/2016

One feature of the input file, is that it uses a semicolon (;) to delimit the tokens on each line of input, rather than whitespace. You will need to use a delimiter statement after you construct your line scanner object.

To see how to construct a line scanner object, go to Chapter 7 PowerPoint slide in the Week 13 folder. So for example, if you create an object called lineScan of type Scanner to process tokens on a given line of input, then you could call the useDelimiter method on your lineScan object, as follows:

lineScan.useDelimiter(";");

This will allow you to tokenize each input line based, not on white space delimiters, but using the semicolon as a delimiter instead.

This is what should be in your Output file after you run your program (this file will most likely be located in the same folder as your Java program).

Dinner expenses : 64.95
Lodging expenses : 236.85
Conference expenses : 500.00
Room Service expenses : 68.20
Spa expenses : 50.00

Submission Requirements:

1. Please be sure to use appropriate prologue comments at the top of your program, Javadoc formatted comments for your methods, as well as inline comments within the body of your code (as needed).

Answer 1

Code:-

import java.util.*;

import java.io.*;

public class Main

{

public static void main(String[] args) throws FileNotFoundException

{

String infile;//input file name

String outfile;//output file name

Scanner sc = new Scanner(System.in);

System.out.print("Enter input file name: ");

infile=sc.nextLine();

Scanner inputScanner=new Scanner(new FileReader(infile));

//do all the computations here

inputScanner.useDelimiter(";");

double conf=0;//conference expense

double lodge=0;//logding expense

double dinner=0;//dinner expense

double spa=0;//spa expenses

double room=0;//room service expenses

while(inputScanner.hasNextLine())//taking input till there exists a line

{

String[] temp= inputScanner.nextLine().split(";");//splitting the input according to delimiter

double x=Double.parseDouble(temp[2]);

if(temp[1].charAt(0)=='C')

{

conf=conf+x;

}

else if(temp[1].charAt(0)=='S')

{

spa=spa+x;

}

else if(temp[1].charAt(0)=='D')

{

dinner=dinner+x;

}

else if(temp[1].charAt(0)=='L')

{

lodge=lodge+x;

}

else

{

room=room+x;

}

}

System.out.printf("Enter output file name: ");

outfile=sc.nextLine();

PrintStream ps = null;//defining the printstream

try//handling exception

{

ps=new PrintStream(outfile);

}

catch (Exception e)

{

System.out.println("Could not open file!");

}

//writing the answer to the output file

ps.print("Dinner Expenses: ");

ps.println(dinner);

ps.print("Lodging Expenses: ");

ps.println(lodge);

ps.print("Conference Expenses: ");

ps.println(conf);

ps.print("Room Service Expenses: ");

ps.println(room);

ps.print("Spa Expenses: ");

ps.println(spa);

return;

}

}

Snippets:-