Added on Saturday, 10 Dec. You should study for and while loops, starting with #8 below (answers at a link on that page).

Then look at #4 and #5, at #2 and #3. All these are fairly easy.

After these, try #6. I give the answer to a simple version of #7, but the full question is hard.

#9, and both projects in #10 are all pretty hard. If you are having trouble in the course, you would be better off looking over some of the simpler examples involving classes, since I'll have something about them. (Good luck!)

Note: After you have worked on the problems below, you can look at Selected Answers.

• Week 15 Lectures gives initial review material. You should work on the the "For Loops" material and on Activities 1 and 3 in this lecture. I have rewritten Activity 3 below on this page under the heading "Sample Questions".
• Week 16 Lectures gives two old Project 3 assignments along with solutions, for you to work on and look over.

• Review for Exam1
• Review for Exam2

• Material you are responsible for:
  • Week 13 Lectures While Loops
  • Week 14 Lectures Do-while Loops
  • Week 15 Lectures For Loops and Review

  • Lab 11 Designing and Implementing a Class using the while Loop The NewtonsSquareRoot Class
  • Lab 12 Designing and Implementing a Class using the for Loop The Depreciation Class

  • Extra Materials Solutions to lecture activities, hints about labs, and other stuff

  • Project 1 The RabbitPopulation Class
  • Project 2 The CoffeeMachine Class
  • Project 3 The Series Class

• How to study: Do not just read the material over, but instead start up JBuilder and try out many of the pieces of code inside actual Java programs.

• Topics:
  • Classes: This remains the most important topic.
    • See Basic parts of a class: Student class These include:
      • A class that will be instantiated (using new).
      • A class with a main method that will do the instantiatino (with us, its name usually has Test at the end).
      • "Private data members" in the first class above. They are also called "instance variables". (With us, the name usually starts with my.)
      • One or more "constructors", with "formal parameters". The constructor name has to be the same as the class name.
      • Various methods, including "public accessor methods" (name usually starts with get), and public and private helper methods. Methods have parameters and we can declare "local variables" inside a method.
    • Also see many worked-out examples on the page: Extra Materials

  • Data types (primitive and objects), operators on primitive types, precedence of operators: See Review for Exam2.

  • if-else statements: See Lectures for weeks 10, and 11.

  • loops: while, for, do-while: See Lectures for weeks 13, 14, and 15.

• classes: Probably some question about writing a class to represent something, and writing a test class to create an instance of the given class. This is what we've been doing all semester long.

• primitive types and operators:
  1. Write Java code that will start with a certain number of seconds, and will convert to hours, minutes, and seconds, where "hours" and "minuters" are as large as possible:

     int time = 74747;  // or some other value in seconds
     int hours = ...;   // fill in for ...
     int minutes = ...; // fill in for ...
     int seconds = ...; // fill in for ... 
     System.out.println(time + " seconds is\n   " +
        hours + " hours\n   " +
        minutes + " minutes\n   " +
        seconds + " seconds\n   ");
       

• if-else:
  2. Write a short if statement (no else) that will check if an int is inside the range from 2 to 10 (inclusive) and will print "In range" if this is so.

  3. Write another short if statement (no else) that will check if an int is not inside the range from 2 to 10 (inclusive) and will print "Out of range" if this is so.

• loops:
  4. Translate the following while loop to a for loop that does the same thing:

     int i = 1;
     int sum = 0;
     while (i < 10) {
        sum = sum + i*i;
        i++;
     }
     System.out.println("sum: " + sum);
       

  5. Translate the following for loop to a while loop that does the same thing:

     for (int k = 10; k >= 1; k--) {
        System.out.print(k);
        // Note: below was "k != 10" in error earlier
        if (k != 1) System.out.print(", ");
     }
     System.out.println();
       

  6. Redo the example that we worked on in class: use a for loop to calculate 100000 terms of the following sum. Compare the result with Math.PI*Math.PI/6.0.

     1 + 1/22 + 1/32 + 1/42 + 1/52 + ...
       

  7. Write a code segment in Java that will start with an amount of money (a double amount), and a number of years (an int years), and an interest rate (a double rate). Use a loop to get the amount of money at the end of this time, applying the interest each year. Compare this amount with the amount you would have if you applied the interest 4 times a year. (You apply 0.25*rate a number times equal to 4*years.)

  8. Here are some more sample questions: Practice with loops.   Answers.
     Just focus on the "First Starting Point" and the "Second Starting Point": this amounts to 6 exercises for "while" loops and 6 for "for" loops.

• Everything (classes, if-else, loops, operators):
  9. Activity 3: the TeacherSalary Class. (taken from the Week 15 lecture).

  10. Two old Project 3 assignments along with solutions: Review Projects. (This is the Week 16 lecture.)