Last Updated: 2017-09-17 Sun 14:20

CSCI 1103 Lab02: Simple Input



Table of Contents

1 Rationale

Completing this lab will teach some basic input/output skills. In particular, basic methods to retrieve integers and doubles from the user via the TextIO class will be needed apprising students to the basics of getting dynamic behavior from their programs.

Associated Reading

Eck Chapter 2
Chapter 2 discusses basic input using the TextIO class. Make sure to understand the use of the TextIO.getInt() and TextIO.getDouble() methods.

2 Download Lab Code and Setup

As in Lab01, download the code pack linked at the top of the page. Unzip this which will create a folder and create your files in that folder.

File State Notes
PARTNERS.txt Edit Fill in your name and the name of your partner in this text file Provided Allows easy input calls like TextIO.getInt() Testing Tests for problem 1 Testing Tests for problem 2
junit-1103.jar Testing For testing, don't try to edit this one Create Create this file for Problem 1 Create Create this file for Problem 2

3 Problem 1: Burgers (TESTED)

Create a file named which will print a welcome message and prompt the user to enter some simple information. The overall usage of the program will look like the following.

> javac
> java Burgers
Welcome to Good Burger,
Home of the Good Burger
May I take your order?
Burgers: $2.55
Fries:   $0.99
Tax:      7.2%
Number of burgers: 
Number of fries: 
Total: $16.14
Tax: $1.1620800000000002
Grand Total: $17.30208

A few notes to save you trouble.

  • The lines with a 4 and 6 above are input, stuff the user should type.
  • Print the prices with fixed strings as in
    System.out.println("Burgers: $2.55");

    While this is generally a bad practice, printing numbers with a specific number of decimal places takes a bit of effort and will be covered later.

  • Make sure to use the TextIO.getInt() method to retrieve integers from the user to calculate their order.
  • Don't worry about the messy output numbers at the end like
    Tax: $1.1620800000000002

    Printing with a specific number of decimal places will be covered soon but if you are curious about it now, ask your TA about the System.out.printf( ... ) method.

4 Problem 2: Gratuity (TESTED)

Create a file named which will prompt the user for a bill, the amount of gratuity (tip) they would like to leave, and the number of people involved in the meal/outing. The program will then print the overall total bill and the amount each person should pay. Below are sample runs.

> java Gratuity
Total bill (ex: 34.56):
Tip percentage (ex: 15.5):
Number of people (ex: 4):
Total with tip: $105.0
Each person pays: $105.0

> java Gratuity
Total bill (ex: 34.56):
Tip percentage (ex: 15.5):
Number of people (ex: 4):
Total with tip: $53.00906
Each person pays: $17.669686666666667

Some notes

  • You'll need to use the TextIO.getDouble() method here as some of the numbers are floating point values.
  • For the number of people, either an integer or a floating point number should work. Choose what you feel is appropriate.
  • The tip is entered as a number but should be converted to a fraction by dividing by 100.
    • 7.5% tip should become 0.075
    • 23.99% tip should become 0.2399

5 Getting Credit for this Lab

5.1 Demonstrate your code to Lab Staff (40%)

You should feel free at any time to get help from lab staff as you get stuck on the exercises.

By the end of the lab, make sure to demonstrate your code to a staff member. This will ensure that you receive full credit on the lab. Staff might ask you to

  • Change what is printed
  • Compile and run on the command line
  • Run tests in DrJava or on the command line
  • Show how to zip the folder with your programs in it

Be ready to do any or all of these.

5.2 Zip and Submit (60%)

Ensure that file PARTNERS.txt has your name and the name of your partner in it. This fill is located with the other Java files for the lab and can be edited with DrJava.

Once your are confident your code is working, you are ready to submit. Ensure your folder has all of the required files. Create a zip archive of your lab folder and submit it to blackboard.

On Canvas:

  • Click on the Assignments section
  • Click on the appropriate link for this lab
  • Scroll down to "Attach a File"
  • Click "Browse My Computer"
  • Select you Zip file and press OK

Author: Chris Kauffman (
Date: 2017-09-17 Sun 14:20