Example. Let us explore the concept of tokens by looking at this C# program. We see the program and then break it up into individual tokens.
Types Types of tokens include keywords (class), identifiers (Program), literals (2) and operators (=).
static void Main()
int test = 2;
float item = 5.5f;
char unit = 'e';
string basic = "c#";
Identifiers are arbitrary names in your C# program.
This includes Program, Main, test, item, unit and basic.
Many keywords are reserved by the C# language.
These include class, static, void, int, float, char and string.
Literals are constant values you can use in your program.
These include 2, 5.5f, 'e' and "c#".
Literals include the enclosing quotation marks.
For the literal 5.5f, the numeric suffix is included in the literal.
This is a real-literal.
These are characters in your program that are part of the scope
structure, or assignment and arithmetic statements.
Some operators, such as && are considered a single token.
The characters () are separate tokens.
Specification. For more material like this on the C# language, the specification is available. This material was adapted from page 61 of the C# annotated specification.
A summary. We now know what a token is in the C# language. This can be helpful in understanding how the language is parsed—and how to fix compile-time errors.
Any time you see more closely how the compiler approaches a language, you gain insight into how it should be used. This description provides insight into how the C# compiler views programs.