CSci 2101 Lab 1. Java variables, data types.

Due Tuesday, May 24th at 11:59pm (by e-mail)

25 points

The lab may be done in pairs or individually.


Lab questions

When you are answering these questions, feel free to delete some of the program code or comment out unnecessary print statements. All your newly added code should be in main.

  1. Write a comment at the top of the file with your name(s) and the lab number. Always do this for all work that you do in this class.
  2. Add a statement to multiply two integer (i.e. int) variables, print out the result.
  3. Add a statement to divide two integers, store the result in a variable, and print that variable. What happens when the two numbers cannot be evenly divided? Write a comment in your program to explain the results.
  4. Print out the value of n. Then write
    n = n + 3;
    Print out its value again. Briefly explain (in comments) what happens.
  5. What does n++; do? Briefly explain (in comments).
  6. Based on the four printouts with a a comment "implicit type conversions" explain what happens when division works on a mix of integer and double numbers.
  7. Change the comparison x < 5 to x <= 5, verify that it works as expected.
  8. What happens if you compare characters 'a' and 'b' using <?
  9. Make two deliberate errors in the program that cause it to fail compilation. What changes did you make? What were the error messages? Were they understandable? Comment out the errors.
  10. Come up with two "what if" questions (for instance: what if I assign a double to an int? What if I declare two variables with the same name?). Write down your questions, your tests, and your answers.

How to submit

Send the file with all your comments by email to me: elenam at The subject of the message must be 2101 Lab 1. Make sure to CC your group partner if you worked with another person.

CSci 2101 course web site.

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