Basics of C Programming

Tokens

In a C language, token is either a keyword, a symbol ,an identifier, a constant or a string literal.

A C program consists of various tokens for example, the following C program consists of five tokens −

printf("Hello, World! \n");

1	printf("Hello, World! \n");

The individual tokens are −

printf
(
"Hello"
)
;

printf

(

"Hello"

)

;

Comments are the text in C program and they are ignored by the compiler during compilation and execution.

They start with /* and terminate with the characters */ as shown below −

value of i & j =  10  20

1	value of i & j = 10 20

Anything written within Comment will never execute. You can’t write comments within comments.

In a C language, identifier is a name given to any variable, function, or any other user-defined item.

C language identifier starts with a letter A to Z, a to z, digits (0 to 9) or an underscore ‘_’ followed by zero.

C does not allow punctuation characters such as @, $, and % within identifiers. Here are some examples of acceptable identifiers −

kumar       aditya    abc   move_name   a_123
name70           j      a23b9        myDemo

1 2	kumar aditya abc move_name a_123 name70 j a23b9 myDemo

In a C language keywords are the reserved words whose meaning already explained in a compiler.

These reserved words can’t be used as a variables or identifier names. There are 32 Keywords in C