• You may insert comments to document apps and improve their readability. The C# compiler ignores comments.
• A comment that begins with
// is called a single-line comment, because it terminates at the end of the line on which it appears.
• Comments delimited by
*/ can be spread over several lines.
• A programming language’s syntax specifies rules for creating a proper app in that language.
using directive helps the compiler locate a class that’s used in an app.
• C# provides a rich set of predefined classes that you can reuse rather than “reinventing the wheel.” These classes are grouped into namespaces—named collections of classes.
• Collectively, C#’s predefined namespaces ...