Tokens are among the most crucial elements utilized in the C programming language. In C, tokens represent the smallest individual units of a program that hold relevance for the compiler's functioning.
In a C program, the tiniest measurement unit is referred to as a token. Each word and punctuation mark within a C program is considered a token. The initial step taken by a compiler is to segment a C program into tokens before proceeding with the subsequent compilation tasks.
Alphanumeric symbols serve as tokens within the program. The lexical scanner scrutinizes the symbols present in the input and transforms them into tokens, which subsequently undergo further compilation phases. Tokens can manifest in various forms such as Keywords, Operators, Strings, Constants, Special Characters, and Identifiers. Illustrations of tokens encompass characters like X, #, Y, [, ], and more.
For instance, just as sentences cannot be formed without words, in a similar manner, the C programming language cannot be utilized without tokens. Consequently, tokens are often described as the essential components or foundational building blocks necessary for developing any C program.
What are Terminals?
Terminal symbols, commonly referred to as terminals, are symbols that appear on the right side of rules during the generation process in a formal language. These symbols are fixed and unalterable within the grammar rules, serving as the basic building blocks or tokens of the language.
Characteristics:
There are several characteristics of Terminals in C. Some main characteristics of the Terminals are as follows:
- Terminals are the symbols that makeup strings in the language.
- Lowercase letters, numerals, or other symbols represent Terminals.
- Terminal symbols have no related productions or rules ; they are the final characters that occur in the strings created by the grammar.
- Terminals in a basic language for expressing arithmetic expressions might be +, -, *, /: operators 0, 1, 2,... 9: Parentheses for numerical constants (,).
- Terminals in a language grammar describing short phrases could be:
- Lowercase letters indicate words: a,b,c..etc.
Main Differences between Tokens and Terminal in C
There exist several key distinctions between Tokens and Terminals in the C programming language. Some primary variances between these two entities include:
| Features | Tokens | Terminals |
|---|---|---|
| Definition | Tokens are the smallest meaningful units in source code that reflect language constructs (e.g., identifiers, phrases). | Terminals are symbols in formal grammatical structures used for string creation and derivation. |
Role |
Basis for syntactic and semantic analysis, assisting with code understanding and execution. | The essential symbols which direct parsing according to grammatical rules and provide the backbone of the language's framework. |
| Characteristics | Variable types (identifiers, literals, and operators), each having its own meaning and importance within the language. | Appear in grammar creation rules, specifying the essential units that construct legal strings. |
| Usage | Tokenizes source code in lexical analysis, which is required for syntax checking and semantic analysis. | Parsing, guided derivation, and production of proper language strings are all dependent on it. |
| Abstraction | Assist in the formation of program structures by providing a relevant level of abstraction in code representation. | Elements at the lowest level of language derivation are represented. |
| Context | Tokens work with a compiler or interpreter directly connected to the syntax and semantics of a language. | It is related to formal grammatical theory and language definition in parsing and language derivation. |
| Examples | Tokens include the following: int (keyword), if (control structure), 123 (numeric literal), + (operator), = (assignment operator), and so on. | Terminals can be represented as a, b, c (individual symbols), 0, 1 (numerical values), (,) (parentheses), and so on. |