Tokens in C
A ‘C’ program consists of various tokens and a token is either a keyword, an identifier, a constant, a string literal, or a symbol. For example, the following C statement consists of four tokens .
printf("Hello, World! \n");
In a C program, the semicolon is a statement terminator. That is, each individual statement must be ended with a semicolon. It indicates the end of one logical entity. Given below are two different statements
printf("Hello, World! \n"); return 0;
A ‘C, identifier is a name used to identify a variable, function, or any other user-defined item. An identifier starts with a letter A to Z, a to z, or an underscore ‘_’ followed by zero or more letters, underscores, and digits (0 to 9). C does not allow punctuation characters such as @, $, and % within identifiers. C is a case-sensitive programming language. Thus, Manpower and manpower are two different identifiers in C.
3. Keywords in C
The following list shows the reserved words in C. These reserved words may not be used as constants or variables or any other identifier names.
4. Whitespace in C
A line containing only whitespace, possibly with a comment, is known as a blank line, and a C compiler totally ignores it. Whitespace is the term used in C to describe blanks, tabs, newline characters and comments. Whitespace separates one part of a statement from another and enables the compiler to identify where one element in a statement, such as int, ends and the next element begins. Therefore, in the following statement-
there must be at least one whitespace character (usually a space) between int and age for the compiler to be able to distinguish them. On the other hand, in the following statement −
fruit = apples + oranges; // get the total fruit
No white space characters are necessary between fruit and =, or between = and apples, although you are free to include some if you wish to increase readability.