Code Formatting Standards and Guidelines

Code Formatting Standards

All organizations and companies have specific conventions for formatting code. While these formatting rules may vary from place to place, they are essential for making your code readable and for enabling others to understand, use, and modify your code in the future.

For these reasons, we will be using the following coding standards in this class. Adherence to these standards will be a portion of your grade on each assignment.

Naming Conventions

Use meaningful names!! For example, if your program needs a variable to represent the radius of a circle, call it radius, NOT r and NOT rad.
Use single letter variables ONLY for simple for loop indices.
The use of very obvious, common, meaningful abbreviations is permitted. For example, "number" can be abbreviated as "num" as in numStudents.
Begin variable and function names with lowercase letters
Begin class names with uppercase letters
Use all uppercase for symbolic constants (e.g., public double PI = 3.14;)
Be consistent!
Separate words within identifiers with mixed upper and lowercase. For example,

Variables: grandTotal, circleRadius
Functions: computeArea, saveFile
Classes: CircleTable, PieChart

Whitespace

The most-readable programs are written with prudent use of whitespace (including both blank lines and spaces).

Use blank lines to separate major parts of a source file or function.
Separate declarations from executable statements with a blank line.
File and class header comments begin in the first column, all function definitions are indented one column to the right.
All statements in the body of a function are indented beyond the function definition. Statements inside of a loop or part of an if structure are indented further.
Use spaces around all operators. For example, write "x = y + 5;" instead of "x=y+5;"

File Header Comments

Every source code file should contain a header comment that describes the contents of the file and other pertinent information. It must include the following information:

The assignment number
Your name
Your school e-mail address
The class and section number
The date the assignment was submitted
A description of the contents of the file

For example:

/*****************************************
* Assignment 4
* Name:    Barbara Smith
* E-mail: bsmith22@brynmawr.edu
* Course:      CS 110 - Section 01
* Submitted:    1/10/2011
*
* The main driver program for project 4.
* This program reads the file specified as the first command line
* argument, counts the number of words, spaces, and characters and
* displays the results in the format specified in the project description.
*
***********************************************/

In-Line Comments

The basic rule of thumb is that you should be able to delete all of your code and then regenerate a working program from only the comments.

Comments explain what your code does; they do not describe how it does it.
Well-structured code will be broken into logical sections that perform a simple task. Each of these sections of code (typically starting with an 'if' statement, or a loop or a 'switch') should be documented.
A particularly important line of code should also be commented.
Do not comment every line of code. Trivial comments (e.g., //increment x) are worse than no comments at all.

An in-line comment appears above the code to which it applies and is indented to the same level as the code. For example:

// increment all the odd values in the array
int arrayLength = array.length;
for (i = 0; i < arrayLength; i++) {
    // add 1 only to the odd values
    if (array[i] % 2 == 1) {
        array[i] = array[i] + 1;
    }
}

Endline comments should very rarely be used, and then only to explain particular aspects of a line, such as what a variable means or some pecularity:

int width = widestXCoord/2 % 11; // divisor must always be a prime number

Indentation Styles

Choose one of the two styles and use it consistently

if (condition) {                                     if (condition)
    ...                                              {
} else if (condition) {                                  ...
    ...                                              }
} else {                                             else if (condition)
    ...                                              {
}                                                        ...
                                                     }
                                                     else
                                                     {
                                                         ...
                                                     }

for (loop control expressions) {                     for (loop control expressions)
    ...                                              {
}                                                        ...
                                                     }

while (condition) {                                  while (condition)
   ...                                               {
}                                                        ...
                                                     }

do {                                                 do
   ...                                               {
} while (condition);                                     ...
                                                     } while (condition);


switch (variable) {                                  switch (variable)
   case constant1:   ...                             {
        break;                                           case constant1:   ...
   case constant2:   ...                                      break;
        break;                                           case constant2:   ...
   case default:     ...                                      break;
}                                                        case default:     ...                                                      }