ou have seen a basic structure of C program, so it will be easy to understand otherbasic building blocks of the C programming language.
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 five tokens:
printf("Hello, World! \n");
Comments
Comments are like helping text in your C program and they are ignored by the compiler. They start with /* and terminates with the characters */ as shown below:
/* my first program in C */
Identifiers
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 or 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. Here are some examples of acceptable identifiers:
mohd myname50 zara_temp a_123 retVal
Keywords
The following list shows the reserved words in C. These reserved words may not be used as constant or variable or any other identifier names.
auto else Long switch break enum register typedef case extern return union char float short unsigned const for signed void continue goto sizeof volatile default if static while do int struct _packed double