Coding Style

• Each block of code must be indented 4 spaces to the right of its parent block. A block is any section of code enclosed between curly braces ({}). If you use the introcs installer to set up Dr. Java as part of Homework 0, it will be configured this way automatically. You can re-indent the current line by pressing TAB. You can reindent a whole section by selecting it and pressing TAB. You can reindent the entire file by selecting everything (Cmd-A on Mac, Ctrl-A on Windows), then hitting TAB. Do not indent your code manually with spaces, let Dr. Java do it.
• There is no excuse for improperly indented code. Ever. Whenever you start typing a new line of code, press TAB to make sure your cursor is in the right place. Whenever you cut and paste, or insert code, select the region around it and press TAB to reindent. Badly indented code is impossible for humans to read, and impossible to debug. If Dr. Java automatically indents your code in a way you don't expect, you have a bug. Usually you are missing a semi-colon or curly brace.
• If your code is not properly indented in office hours, we may refuse to help you. There is no rule that is more universally agreed upon than the importance of correct indentation. There is also no single, simple thing you can do that will help you more than correctly indenting your code.

• Variable names and function/method names start with a lower-case letter. If the name is a composite of multiple words, each subsequent word starts with a capital letter. For example, "var" is an acceptable name for a variable, and "thisIsAVariableName" is also an acceptable name for a variable. The names "ThisNameBeginsWithACapitalLetter" and "this_name_contains_underscores" are not acceptable for variables in CIS 110.
• The same rules apply to functions and methods (we introduce functions and methods in the course of the semester). The first convention, that variable names begin with a lower-case letter, is very widely accepted. On the other hand, many projects and companies prefer to separate words with underscores ("_") rather than using capital letters.
• As an exception to the above rule, constant variable names should be all upper-case. Constant variables are variables whose value never changes. Alternatively, think of these as symbolic names for particular values. The canonical example is a variable whose value is 3.14159... This variable would be named "PI" rather than "pi". This convention is also widely accepted.
• Class names should begin with a capital letter. If the name is made up of multiple words, each word should begin with a capital letter. Once again, this is a widely accepted convention in object-oriented languages. It is often difficult to tell from context whether a name refers to a variable or a class. By following the capitalization conventions your code becomes much easier to read and understand.

• Use a single space on either side of mathematical operators (+, -, *, /). For example, write "x + y", not "x+y".
• Put a space before an opening curly brace, or else put the brace on its own line. Be consistent in your choice. Put the close curly brace on its own line.
• Put a space between all function arguments. Example: use PennDraw.rectangle(0.5, 0.5, 0.25, 0.25). Compare this to PennDraw.rectangle(0.5,0.5,0.25,0.25). In the second case it is not easy to read the arguments and see where one ends and the other begins.
• Do not put a space before the square brackets for an array. For example, write "String[] args" and "args[0]", not "String [] args" or "args [0]".
• The spacing around parentheses corresponds to how you would use them in English and math:
  • Put spaces outside the parentheses, but not inside them, when they are used to group mathematical computations. For example, write "a + (b + c)", not "a +(b + c)" or "a + ( b + c )".
  • Put spaces outside the parentheses, but not inside them, when they are part of a loop or conditional (if, for, or while). For example, write "if (x > 5) {", not "if(x > 5){" or "if ( x > 5 ) {".
  • Do not put spaces around parentheses when they are part of a function call. For example, write "System.out.println("hello, world.")", not "System.out.println ("Hello, world.")" or "System.out.println( "Hello, world." )".

	/*  Name: Benedict Brown
	 *  PennKey: bjbrown
	 *  Recitation: 200
	 *
	 *  Execution: java HelloWorld
	 *
	 *  Prints "Hello, World". By tradition, this is everyone's first program.
	 *
	 */

Everyone agrees on the importance of a file header, but every project and company has its own format. It's common to include the name of the file, copyright notice, date, and list of authors at the very top to assert ownership. Some projects include a list of changes to the file, a list of any other files the program needs, etc. Depending on the country, failure to assert copyright at the top of file may implicitly release it into the public domain. (This was true in the United States until 1989. Early source code to the UNIX operating is widely assumed to be in the public domain because it was distributed without copyright notices before that time. AT&T famously settled a lawsuit against the University of California over the UNIX copyrights when this issue came to light.)