Before you learn any language, not explicitly a programming language, you need to learn its character sets. You form words using those character sets, write sentences, and finally write paragraphs, essays, and so on. Besides that, you need to learn about the grammar of that language to form a sentence correctly. The grammar specifies the syntax, semantics, and morphology of a language. After completing this chapter, you will learn the necessary tokens needed to write a C program, including character sets, keywords, variables, and constants. Writing any program requires knowledge of these tokens. To perform any operation, you need to store numbers; for that, you need a variable. To create a variable, you need a data type. These are the first components of any programming language to be mastered before you write complex programs.