CSCI 136

Data Structures  & Advanced Programming

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Style Guide

The way you present your program is just as important as having a correct program. While having good comments or good variable names will not affect the correctness of your program, it will make it easier to read your program. It is important that others be able to understand your code so that they can modify your code if they have to. A large fraction of your lab grade will be determined by your programming style.

This is a guide to help you better understand what we are looking for when we look at your programs. As the semester progresses there will be steeper penalties for stylistic mistakes. So, get into the habit of writing good labs from the beginning. Our class examples the textbook should serve as additional examples of well-formatted and documented code. Always look over your code and your style before handing in your labs.


Always write accurate yet concise comments:

You should write comments for:

  1. Class (Program): At the top of each class, you should write your name, date of creation, and a brief description of what the class is for. If you decide to do more than the assignment requested, you should describe these "extra" features in the program under the class description. Sometimes it's hard to tell a bug from a feature.
  2. Methods: Above each method heading there should be a brief description of what the method does. You should also describe what each parameter means and what the return result means. If the method code is simple you do not need to comment in the method body. If the method body is complicated, you might want to add some comments to certain areas that you deem to be complicated.
  3. Variables and constants: In general, variables and constants should all have comments as to what they are used for. For example a good comment for your variable Card hand[] in our cards examples would be: // the cards currently held by the player . Occasionally several closely related variables or constants can be grouped together under the same comment.

Blank Lines

Blank lines are used to delineate different areas of the code. The instance variable declarations at the top of your program should be separated from the header of the class and the header of the first method. There should always be space between methods. It is advisable to break up long method bodies and long declarations into logical pieces. Always start a new line after the semicolon. Always leave a blank line before a comment line.


You should always choose names that suggest the meanings of the things being named. If the purpose of a method is to draw a rectangle, then a good name for that method is drawRect. If there is a variable used to store the cards held by a player, suitable names may be playerHand or hand.

Also, follow the Java capitalization convention:

Instance variables should never be declared to be public. Instance variables should only be used when a value must be saved for use after a constructor or method has been completed. Otherwise local variables should be used.


Your program should be organized as neatly as possible. All method headers should be aligned with each other. Variables should also be aligned. You should indent consistently. A good heuristic is that whenever you see an open curly brace you should indent your code 2 or 3 spaces until the ending curly brace. See the example below.

The following is a guide to what your code should look like. There are variations that are acceptable, but this is a good format to follow.

 * Name:
 * Lab:
 * Description of Class and Extras...
public class ClassName {
  type1 firstVariable;               //comment for firstVariable
  type2 secondVariable;              //comment for secondVariable
   * This variable needs a really long comment that doesn't fit on 
   * the end of the line with the declaration
  typeN nthVariable

   * comments for method
  public void methodName1(...) {
    code line 1;
    if (condition) {
      code line 3;
      code line 4;
    code line 5;

   * comments for method
   * param1 is the first parameter
   * Returns a value that ...
   * pre/post conditions (if they exist)
  public int methodName2(type1 param1) {