Lexer and Parser in C

Lexer and Parser in C

Lexer and Parser are two major programs that have been used  inC programmingfor many years. They are used hand in hand to analyze the syntax of C programming to help produce the best and most effective software applications. But students and programmers who are just getting started with C language may have difficulties understanding these two terms. That’s why our Lexer and Parser in C homework help experts have discussed the two programs in depth to make them much easier to understand.


Also known as a tokenizer or scanner, a Lexer is a program used to convert a sequence or series of characters (like in a web page or computer program) into a series of tokens (strings with an identified meaning). It transforms the original input into a form that can be managed better and more easily by the parser that will work on the data at a later stage.

One important role of the Lexer is discarding whitespace between tokens. When creating C programs, you want the Lexer to get rid of the whitespace. If this task is not handled by the Lexer before the Parser takes over, then the Parser will have to check and discard the whitespace between every token, which can be quite annoying and could consequently increase the program development time.

However, in some programming languages like Python,  whitespace is important for software development and it is used to identify various blocks of code. But even then, a Lexer is still used to differentiate between relevant whitespace and irrelevant one. Basically, you want the Lexer to point out which whitespace is appropriate or relevant for parsing. To learn more about Lexer in C programming, connect with our Lexer and Parser assignment help experts.


Parser is the software used to analyze the tokens released by the Lexer, in a process known as parsing. It performs the most difficult part of the program development, and hence most C programmers consider it more important than the Lexer. If Lexer and Parser were to be compared in the context of syntax analysis, then the lexer would be classified as a helper, because its job is basically to assist the parsing process.

The Parser gives its output in the form of a code, usually a tree. This tree can be either an abstract syntax tree or a parse tree. While these two are often categorized as trees, there is a slight difference in the intermediate elements contained in both and how each tree represents the actual code. The tree structure is one of the most preferred way of parsing in C as it makes it easy for programmers to work with different levels of code in detail.  To have this topic expounded further, liaise with our Lexer and Parser in C homework help experts.

Lexerless Parser

A Lexerless Parser, also known as a scannerless Parser, is a Parser that carries out both the tokenization and parsing process in one step. In most instances, having a separate Lexer and a Parser is preferred because it allows programmers to create clearer objectives and a Parser that is more modular. A Lexerless Parser is ideal in programming languages where differentiating a Lexer or Parser is challenging or unnecessary. It can also be used to handle languages like C, where traditional lexing is difficult. This is because, a Lexerless Parser can handle complex tokenizations more easily. If you are still having trouble understanding the concept of Lexer and Parser in C programming and would like us to shed more light on the same, reach out to our Lexer and Parser assignment helpers.