Every programmer and programming language has a preferred variation on how to format code. Here are my best suggestions for the languages I tend to code.

• Use spaces, not tabs. The definition (display width) of a tab can vary from one editor and platform to the next. A space is always a space.
• Use two (2) spaces to indent a block of code.
• Always wrap code blocks with curly braces { } even if they’re optional for a single line of code. Someone will, eventually, want to add a second line of code to the block and will, as a rule, forget to add the curly braces.
• The opening curly brace of a block should be on the same line as its opening statement.

      public String getFirstname () {
      while (i < 5) {
  

• The closing curly brace should be on its own line.

      }
  

• Leave a blank line after closing a block of code (including the end of a method), unless followed immediately by another closing curly brace.

              }
            }
          }
  

• Place a comment after closing a block of code when there’s a series of closing curly braces.

              } // if
            } // method
          } // class
  

• always put one (1) space before and after binary operators.

      x = x + 5;
      while (i < 5) {
  

• Put one (1) space before the opening parenthesis and after the closing parenthesis in statements (for, while, if, and so on) or function calls.

      for (int i = 0; i < 100; i = i + 1) {
      while (x != 2) {
      if (isPrime (n)) {
      sin (5)
      getPrice ()
  

• Indent each new code block.

      for (int i = 0; i < 100; i = i + 1) {
        if ((i % 2) != 0) {
          if (isPrime (i)) {
            System.out.println (i);
          } // if
        } // if
      } // for
  

• Use the variable naming convention used in your language of the moment: camelCase or under_scores.
• Use meaningful variable and method names. For method names, verbNoun them.

      numStudents
      totalVacationDays
      getFirstname ()
      computeSalary ()
  

• Use single letter variable names iff the letter reflects a standard (recognizable) convention.
  • i, j, k for an index (counter) variable
  • x, y, z for coordinates in 3-space
  • a, b, c for coefficients
  • m, n for the number of items in a collection
  • r for the radius of a circle
  • w, h for the width and height of an object
• Use ALL_UPPERCASE for constants (fixed values, like PI)
• Use white space to make your code more readable.
• Comments should describe why you’re doing something, not how. The code tells me how you’re doing it.