In this book, you will find a number of styles of text that distinguishe between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The last clause in the try statement should be on Exception catch(e) or, even better, a simple catch(e) to stop any type of error or exception."

A block of code is set as follows:

import 'dart:math';                                      (1)

void main() {
  var n = 0; // number of rabbits                        (2)

  print("The number of rabbits increases as:
");        (3)
  for (int years = 0; years <= 10; years++) {            (4)
    n = (2 * pow(E, log(15) * years)).round().toInt();   (5)
    print("After $years years:	 $n animals");           (6)
  }
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

try {
  int inp = int.parse(input);
} on FormatException {
  print ('ERROR: You must input an integer!'),
}

Any command-line input or output is written as follows:

Observatory listening on http://127.0.0.1:49621

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "Navigate to Tools | Preferences | Run and Debug, and change Break on Exceptions to None".